Catalyst compositions for hydroformylation and methods of use thereof

ABSTRACT

Disclosed are highly active cationic cobalt phosphine complexes, both mono- and bimetallic, that can catalyze hydroformylation reactions. The disclosed catalysts can be utilized in methods that provide reaction processes that are hundreds of times faster than high pressure HCo(CO)4 or phosphine-modified HCo(CO)3(PR3) catalysts and operate at considerably lower pressures and temperatures. Also disclosed are methods of hydroformylation using the described transition metal complexes. This abstract is intended as a scanning tool for purposes of searching in the particular art and is not intended to be limiting of the present disclosure.

CROSS-REFERENCE TO RELATED APPLICATIONS

This Application claims the benefit of U.S. Provisional Application No.62/682,192, filed on Jun. 8, 2018, which is incorporated herein byreference in its entirety.

BACKGROUND OF THE DISCLOSURE

Hydroformylation is a reaction that converts alkenes, CO, and H₂ intoaldehyde products with linear and branched regioselectivities. Sidereactions include alkene isomerization and hydrogenation. ExxonMobil hasa hydroformylation plant in Baton Rouge that uses the well-knownHCo(CO)₄ catalyst system, which was originally discovered by Otto Roelenin Germany in 1938. HCo(CO)₄ is considered the most active cobaltcatalyst system known, but has a major weakness in that it decomposes toinactive cobalt metal unless high enough pressures of CO gas are used.As the temperature of the reaction increases, the CO partial pressureused must increase logarithmically in order to keep HCo(CO)₄ fromdecomposing to cobalt metal. ExxonMobil runs their hydroformylationprocess using a mixture of branched internal alkenes (C₆ to C₁₂) around180° C. and 250-300 bar of H₂/CO. Under these conditions, aldehydes canbe produced with about a 2:1 linear to branched (L:B) selectivity. Thisis often called the high-pressure or unmodified cobalt technology.Because the HCo(CO)₄ catalyst has low hydrogenation activity, thealdehydes are hydrogenated to alcohols in a subsequent catalytic step.

Shell Chemical discovered that the addition of an alkylated phosphineligand to the cobalt catalyst system generated a less active but farmore regioselective catalyst for producing linear aldehydes. Thephosphine ligand keeps the cobalt catalyst, HCo(CO)₃(PR₃), fromdecomposing as easily to cobalt metal. This allows Shell to run theirhydroformylation plant under milder pressures and temperatures: 180-200°C. and 60-70 bar. The phosphine ligand increased the aldehyde L:Bselectivity to 8:1, which is very desirable for Shell's market. Thephosphine ligand also increases the activity of the cobalt catalystfairly dramatically for hydrogenating the aldehyde to alcohol, which isalso Shell's desired product. One moderately serious problem with theShell catalyst is that it also hydrogenates alkene into alkane,consuming about 15-20% of the valuable alkene starting material tosemi-worthless alkane.

Despite advances in research directed to catalysts and methods forhydroformylation, there remain a need for improved, efficient, andaccessible catalysts and methods for this reaction. These needs andother needs are satisfied by the present disclosure.

SUMMARY

In accordance with the purpose(s) of the disclosure, as embodied andbroadly described herein, the disclosure, in one aspect, relates tocompositions comprising cationic transition metal phosphine complexes,both mono- and bimetallic, e.g., a cobalt phosphine complex, that can beused to catalyze hydroformylation reactions, and methods of making same.The disclosed catalysts can be utilized in methods that provide reactionprocesses that are hundreds of times faster than high pressure HCo(CO)₄or phosphine-modified HCo(CO)₃(PR₃) catalysts and operate atconsiderably lower pressures and temperatures.

Disclosed are compounds of formula I, or a salt, solvate, orstereoisomer thereof:

wherein in formula I: X is selected from the group consisting of O, NR⁸,and CR⁹R¹⁰, wherein R⁸, R⁹, and R¹⁰ can be the same or different and areeach independently selected from the group consisting of H, C₁-C₅ alkyl,C₂-C₅ alkenyl, C₁-C₅ alkoxy, C₁-C₂₀ alcohol, C₃-C₆cycloalkyl, C₃-C₆cycloalkoxy, C₆-C₁₀ aryl, C₆-C₁₀ alkaryl, C₆-C₁₀ aralkyl, C₄-C₁₀heteroaryl, and combinations thereof; or optionally R⁹ and R¹⁰ cantogether form a C₃-C₆ cycloalkyl ring; each occurrence of Yindependently represents a divalent linking group selected from thegroup consisting of C₁-C₆ alkyl, C₁-C₆ alkenyl, C₆-C₁₄ aryl, C₄-C₁₄heteroaryl, O, NR⁴, and combinations thereof; each occurrence of R¹, R²,R³, and R⁴ is independently selected from the group consisting of C₁-C₂₀alkyl, C₁-C₈ alkoxy, C₁-C₂₀ alcohol, C₃-C₆cycloalkyl, C₃-C₆ cycloalkoxy,C₆-C₁₀ aryl, C₆-C₁₀ alkaryl, C₆-C₁₀ aralkyl, C₄-C₁₀ heteroaryl, andcombinations thereof; or R² and R³ may optionally be joined together toform a ring; or optionally one of R¹ and one of either R⁹ or R¹⁰ maytogether form a ring; M¹ and M² each independently represent atransition metal selected from the group consisting of Fe, Co, Ni, Cu,Ru, Rh, Pd, Ir, and Pt, and M¹ and M² can be the same or different; n isan integer between 0 and 4, wherein the value of the number n for theligand L¹ depends on the transition metal M¹ and is selected such thatthe transition metal M¹ has 14, 15, 16, 17, 18, or 19 valence electrons;m is an integer between 0 and 4, wherein the value of the number m forthe ligand L² depends on the transition metal M² and is selected suchthat the transition metal M² has 14, 15, 16, 17, 18, or 19 valenceelectrons; p is an integer between 0 and 4; and L¹ and L² can be thesame or different and each occurrence is independently selected from thegroup consisting of trialkylphosphine, tricycloalkylphosphine, diethylether, tetrahydrofuran, H₂O, CO, acetylacetonate, acetate, C₁-C₆alkoxide, acetonitrile, cyclooctadiene, N(R¹¹)₃, N(R¹¹)₂, C₁-C₆ alkyl,C₄-C₁₀ heteroaryl, C₄-C₁₀ heterocycle, H, Cl, Br, I, and F; wherein R¹¹is H, alkyl, cyclcoalkyl, heteroalkyl, or heterocyclic.

Also disclosed are compounds of formula (II), or a salt, solvate, orstereoisomer thereof:

wherein in formula (II): each occurrence of R⁵ and R⁶ is independentlyselected from the group consisting of C₁-C₂₀ alkyl, C₁-C₂₀ alkoxy,C₁-C₂₀ alcohol, C₃-C₆ cycloalkyl, C₃-C₆ cycloalkoxy, C₆-C₁₀ aryl, C₆-C₁₀alkaryl, C₆-C₁₀ aralkyl, or combinations thereof; or R⁵ and R⁶ mayoptionally be joined together to form a ring; Z represents a divalentlinking group selected from the group consisting of C₁-C₆ alkyl, C₁-C₆alkenyl, C₆-C₁₄ aryl, C₄-C₁₄ heteroaryl, O, NR⁴, and combinationsthereof; M is a transition metal selected from the group consisting ofFe, Co, Ni, Cu, Ru, Rh, Pd, Ir, and Pt; o is an integer between 0 and 4,wherein the value of the number o for the ligand L depends on thetransition metal M and is selected such that the transition metal M has14, 15, 16, 17, 18, or 19 valence electrons; q is an integer between 0and 4; and each occurrence of L can be the same or different and isselected from the group consisting of trialkylphosphine,tricycloalkylphosphine, diethyl ether, tetrahydrofuran, H₂O, CO,acetylacetonate, acetate, C₁-C₆ alkoxide, acetonitrile, cyclooctadiene,N(R¹¹)₃, N(R¹¹)₂, C₁-C₆ alkyl, C₄-C₁₀ heteroaryl, C₄-C₁₀ heterocycle, H,Cl, Br, I, and F; wherein R¹¹ is H, alkyl, cyclcoalkyl, heteroalkyl, orheterocyclic.

Also disclosed are methods of making the compounds of formula I andformula II.

Also disclosed are methods of preparing an aldehyde-containing compound,the method comprising contacting an alkene-containing compound with adisclosed cationic transition metal phosphine complexes, e.g., acompound of formula I and/or formula II, in the presence of hydrogen(H₂) and carbon monoxide (CO), whereby the alkene is converted to analdehyde.

Other systems, methods, features, and advantages of the presentdisclosure will be or become apparent to one with skill in the art uponexamination of the following drawings and detailed description. It isintended that all such additional systems, methods, features, andadvantages be included within this description, be within the scope ofthe present disclosure, and be protected by the accompanying claims. Inaddition, all optional and preferred features and modifications of thedescribed embodiments are usable in all aspects of the disclosure taughtherein. Furthermore, the individual features of the dependent claims, aswell as all optional and preferred features and modifications of thedescribed embodiments are combinable and interchangeable with oneanother.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the present disclosure can be better understood withreference to the following drawings. The components in the drawings arenot necessarily to scale, emphasis instead being placed upon clearlyillustrating the principles of the present disclosure.

Moreover, in the drawings, like reference numerals designatecorresponding parts throughout the several views.

FIG. 1 depicts a hydroformylation reaction.

FIG. 2 comprising FIGS. 2A-2B, depicts the structure of exemplary highlyactive cationic cobalt hydroformylation catalyst precursors of thepresent disclosure. FIG. 2A depicts the structure ofCo₂(acac)₂(rac-et,ph-P4-Ph)]²⁺. FIG. 2B depicts the structure of[Co(acac){(PEt₂)₂(1,2-C₆H₄)}]⁺. Both catalysts have BF₄ counter ions.

FIG. 3 depicts the crystal structure of Ni(F)(CH₃)[d(iPr)pe] showingstick and space-filling models with the same orientation.

FIG. 4, comprising FIGS. 4A and 4B, shows the effect of odd electroncounts and reactivity. FIG. 4A is a scheme depicting an equilibriumbetween exemplary catalyst precursors of the present disclosure andcarbon monoxide (CO). FIG. 4B is a scheme showing reactivity differencesfor substitution reactions for 18e− and 17e− complexes.

FIG. 5 is a scheme showing an updated proposed mechanism for cationicCo(II) hydroformylation with bisphosphine ligands that do not block theaxial coordination sites. Only production of the linear aldehyde productis shown, although a similar mechanism to make the branched aldehyde mayalso be used.

FIG. 6 shows chemical structures for representative disclosed catalystprecursors and ligands and associated ligand abbreviations.

FIG. 7 shows chemical structures for representative disclosed biphenphosligand.

FIG. 8 shows representative data for a high pressure infrared (IR)spectroscopic study of the [Co(acac)(DPPBz)](BF₄) catalyst precursorunder various pressures of pure carbon monoxide as indicated. The IRpeaks for CO and the catalyst precursors are as indicated in the figure.

Additional advantages of the disclosure will be set forth in part in thedescription which follows, and in part will be obvious from thedescription, or can be learned by practice of the disclosure. Theadvantages of the disclosure will be realized and attained by means ofthe elements and combinations particularly pointed out in the appendedclaims. It is to be understood that both the foregoing generaldescription and the following detailed description are exemplary andexplanatory only and are not restrictive of the disclosure, as claimed.

DETAILED DESCRIPTION

Many modifications and other embodiments disclosed herein will come tomind to one skilled in the art to which the disclosed compositions andmethods pertain having the benefit of the teachings presented in theforegoing descriptions and the associated drawings. Therefore, it is tobe understood that the disclosures are not to be limited to the specificembodiments disclosed and that modifications and other embodiments areintended to be included within the scope of the appended claims. Theskilled artisan will recognize many variants and adaptations of theaspects described herein. These variants and adaptations are intended tobe included in the teachings of this disclosure and to be encompassed bythe claims herein.

Although specific terms are employed herein, they are used in a genericand descriptive sense only and not for purposes of limitation.

As will be apparent to those of skill in the art upon reading thisdisclosure, each of the individual embodiments described and illustratedherein has discrete components and features which may be readilyseparated from or combined with the features of any of the other severalembodiments without departing from the scope or spirit of the presentdisclosure.

Any recited method can be carried out in the order of events recited orin any other order that is logically possible. That is, unless otherwiseexpressly stated, it is in no way intended that any method or aspect setforth herein be construed as requiring that its steps be performed in aspecific order. Accordingly, where a method claim does not specificallystate in the claims or descriptions that the steps are to be limited toa specific order, it is no way intended that an order be inferred, inany respect. This holds for any possible non-express basis forinterpretation, including matters of logic with respect to arrangementof steps or operational flow, plain meaning derived from grammaticalorganization or punctuation, or the number or type of aspects describedin the specification.

All publications mentioned herein are incorporated herein by referenceto disclose and describe the methods and/or materials in connection withwhich the publications are cited. The publications discussed herein areprovided solely for their disclosure prior to the filing date of thepresent application. Nothing herein is to be construed as an admissionthat the present invention is not entitled to antedate such publicationby virtue of prior invention. Further, the dates of publication providedherein can be different from the actual publication dates, which canrequire independent confirmation.

While aspects of the present disclosure can be described and claimed ina particular statutory class, such as the system statutory class, thisis for convenience only and one of skill in the art will understand thateach aspect of the present disclosure can be described and claimed inany statutory class.

It is also to be understood that the terminology used herein is for thepurpose of describing particular aspects only and is not intended to belimiting. Unless defined otherwise, all technical and scientific termsused herein have the same meaning as commonly understood by one ofordinary skill in the art to which the disclosed compositions andmethods belong. It will be further understood that terms, such as thosedefined in commonly used dictionaries, should be interpreted as having ameaning that is consistent with their meaning in the context of thespecification and relevant art and should not be interpreted in anidealized or overly formal sense unless expressly defined herein.

Prior to describing the various aspects of the present disclosure, thefollowing definitions are provided and should be used unless otherwiseindicated. Additional terms may be defined elsewhere in the presentdisclosure.

Definitions

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this disclosure belongs. Although any methods andmaterials similar or equivalent to those described herein can be used inthe practice or testing of the present disclosure, the preferred methodsand materials are described.

As used herein, each of the following terms has the meaning associatedwith it in this section.

As used herein, “comprising” is to be interpreted as specifying thepresence of the stated features, integers, steps, or components asreferred to, but does not preclude the presence or addition of one ormore features, integers, steps, or components, or groups thereof.Moreover, each of the terms “by”, “comprising,” “comprises”, “comprisedof,” “including,” “includes,” “included,” “involving,” “involves,”“involved,” and “such as” are used in their open, non-limiting sense andmay be used interchangeably. Further, the term “comprising” is intendedto include examples and aspects encompassed by the terms “consistingessentially of” and “consisting of.” Similarly, the term “consistingessentially of” is intended to include examples encompassed by the term“consisting of”.

The articles “a” and “an” are used herein to refer to one or to morethan one (i.e., to at least one) of the grammatical object of thearticle. By way of example, “an element” means one element or more thanone element.

It should be noted that ratios, concentrations, amounts, and othernumerical data can be expressed herein in a range format. It will befurther understood that the endpoints of each of the ranges aresignificant both in relation to the other endpoint, and independently ofthe other endpoint. It is also understood that there are a number ofvalues disclosed herein, and that each value is also herein disclosed as“about” that particular value in addition to the value itself. Forexample, if the value “10” is disclosed, then “about 10” is alsodisclosed. Ranges can be expressed herein as from “about” one particularvalue, and/or to “about” another particular value. Similarly, whenvalues are expressed as approximations, by use of the antecedent“about,” it will be understood that the particular value forms a furtheraspect. For example, if the value “about 10” is disclosed, then “10” isalso disclosed.

When a range is expressed, a further aspect includes from the oneparticular value and/or to the other particular value. For example,where the stated range includes one or both of the limits, rangesexcluding either or both of those included limits are also included inthe disclosure, e.g. the phrase “x to y” includes the range from ‘x’ to‘y’ as well as the range greater than ‘x’ and less than ‘y’. The rangecan also be expressed as an upper limit, e.g. ‘about x, y, z, or less’and should be interpreted to include the specific ranges of ‘about x’,‘about y’, and ‘about z’ as well as the ranges of ‘less than x’, lessthan y’, and ‘less than z’. Likewise, the phrase ‘about x, y, z, orgreater’ should be interpreted to include the specific ranges of ‘aboutx’, ‘about y’, and ‘about z’ as well as the ranges of ‘greater than x’,greater than y’, and ‘greater than z’. In addition, the phrase “about‘x’ to ‘y’”, where ‘x’ and ‘y’ are numerical values, includes “about ‘x’to about ‘y’”.

It is to be understood that such a range format is used for convenienceand brevity, and thus, should be interpreted in a flexible manner toinclude not only the numerical values explicitly recited as the limitsof the range, but also to include all the individual numerical values orsub-ranges encompassed within that range as if each numerical value andsub-range is explicitly recited. To illustrate, a numerical range of“about 0.1% to 5%” should be interpreted to include not only theexplicitly recited values of about 0.1% to about 5%, but also includeindividual values (e.g., about 1%, about 2%, about 3%, and about 4%) andthe sub-ranges (e.g., about 0.5% to about 1.1%; about 5% to about 2.4%;about 0.5% to about 3.2%, and about 0.5% to about 4.4%, and otherpossible sub-ranges) within the indicated range.

As used herein, the terms “about,” “approximate,” “at or about,” and“substantially” mean that the amount or value in question can be theexact value or a value that provides equivalent results or effects asrecited in the claims or taught herein. That is, it is understood thatamounts, sizes, formulations, parameters, and other quantities andcharacteristics are not and need not be exact, but may be approximateand/or larger or smaller, as desired, reflecting tolerances, conversionfactors, rounding off, measurement error and the like, and other factorsknown to those of skill in the art such that equivalent results oreffects are obtained. In some circumstances, the value that providesequivalent results or effects cannot be reasonably determined. Ingeneral, an amount, size, formulation, parameter or other quantity orcharacteristic is “about,” “approximate,” or “at or about” whether ornot expressly stated to be such. It is understood that where “about,”“approximate,” or “at or about” is used before a quantitative value, theparameter also includes the specific quantitative value itself, unlessspecifically stated otherwise. In such cases, it is generallyunderstood, as used herein, that “about” and “at or about” mean thenominal value indicated ±10% variation unless otherwise indicated orinferred.

As used herein, the term “alkyl,” by itself or as part of anothersubstituent means, unless otherwise stated, a straight or branched chainhydrocarbon having the number of carbon atoms designated (i.e., C₁-C₁₀means one to ten carbon atoms) and includes straight, branched chain, orcyclic substituent groups. Examples include methyl, ethyl, propyl,isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, andcyclopropylmethyl. Other examples include (C₁-C₆)alkyl, such as, but notlimited to, ethyl, methyl, isopropyl, isobutyl, n-pentyl, n-hexyl andcyclopropylmethyl.

As used herein, the term “cycloalkyl” refers to a mono cyclic orpolycyclic non-aromatic group, wherein each of the atoms forming thering (i.e. skeletal atoms) is a carbon atom. In one aspect, thecycloalkyl group is saturated or partially unsaturated. In anotheraspect, the cycloalkyl group is fused with an aromatic ring. Cycloalkylgroups include groups having from 3 to 10 ring atoms. Illustrativeexamples of cycloalkyl groups include, but are not limited to, thefollowing moieties:

Monocyclic cycloalkyls include, but are not limited to, cyclopropyl,cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl.Dicyclic cycloalkyls include, but are not limited to,tetrahydronaphthyl, indanyl, and tetrahydropentalene. Polycycliccycloalkyls include adamantine and norbornane. The term cycloalkylincludes “unsaturated nonaromatic carbocyclyl” or “nonaromaticunsaturated carbocyclyl” groups, both of which refer to a nonaromaticcarbocycle as defined herein, which contains at least one carbon-carbondouble bond or one carbon-carbon triple bond.

As used herein, the term “alkenyl,” employed alone or in combinationwith other terms, means, unless otherwise stated, a stablemono-unsaturated or di-unsaturated straight chain or branched chainhydrocarbon group having the stated number of carbon atoms. Examplesinclude vinyl, propenyl (or allyl), crotyl, isopentenyl, butadienyl,1,3-pentadienyl, 1,4-pentadienyl, and the higher homologs and isomers. Afunctional group representing an alkene is exemplified by —CH₂—CH═CH₂.

As used herein, the term “alkynyl,” employed alone or in combinationwith other terms, means, unless otherwise stated, a stable straightchain or branched chain hydrocarbon group with a triple carbon-carbonbond, having the stated number of carbon atoms. Non-limiting examplesinclude ethynyl and propynyl, and the higher homologs and isomers. Theterm “propargylic” refers to a group exemplified by —CH₂—C≡CH. The term“homopropargylic” refers to a group exemplified by —CH₂CH₂—C≡CH. Theterm “substituted propargylic” refers to a group exemplified by—CR₂—C≡CR, wherein each occurrence of R is independently H, alkyl,substituted alkyl, alkenyl or substituted alkenyl, with the proviso thatat least one R group is not hydrogen. The term “substitutedhomopropargylic” refers to a group exemplified by —CR₂CR₂—C≡CR, whereineach occurrence of R is independently H, alkyl, substituted alkyl,alkenyl or substituted alkenyl, with the proviso that at least one Rgroup is not hydrogen.

As used herein, the term “substituted alkyl,” “substituted cycloalkyl,”“substituted alkenyl” or “substituted alkynyl” means alkyl, cycloalkyl,alkenyl or alkynyl, as defined above, substituted by one, two or threesubstituents. In one aspect, the substituents are selected from thegroup consisting of halogen, —OH, alkoxy, tetrahydro-2-H-pyranyl, —NH₂,—N(CH₃)₂, (1-methyl-imidazol-2-yl), pyridin-2-yl, pyridin-3-yl,pyridin-4-yl, —C(═O)OH, trifluoromethyl, —C≡N, —C(═O)O(C₁-C₄)alkyl,—C(═O)NH₂, —C(═O)NH(C₁-C₄)alkyl, —C(═O)N((C₁-C₄)alkyl)₂, —SO₂NH₂,—C(═NH)NH₂, and —NO₂, In one aspect, one or two substituents are presentand include halogen, —OH, alkoxy, —NH₂, trifluoromethyl, —N(CH₃)₂, and—C(═O)OH. In one aspect, the substituents include halogen, alkoxy and—OH. Examples of substituted alkyls include, but are not limited to,2,2-difluoropropyl, 2-carboxycyclopentyl and 3-chloropropyl.

As used herein, the term “alkoxy” employed alone or in combination withother terms means, unless otherwise stated, an alkyl group having thedesignated number of carbon atoms, as defined above, connected to therest of the molecule via an oxygen atom, such as, for example, methoxy,ethoxy, 1-propoxy, 2-propoxy (isopropoxy) and the higher homologs andisomers. Non-limiting examples include (C₁-C₃)alkoxy, such as, but notlimited to, ethoxy and methoxy.

As used herein, the term “halo” or “halogen” alone or as part of anothersubstituent means, unless otherwise stated, a fluorine, chlorine,bromine, or iodine atom. In one aspect, halo includes fluorine,chlorine, or bromine. In one aspect, halo includes fluorine or chlorine.

As used herein, the term “heteroalkyl” by itself or in combination withanother term means, unless otherwise stated, a stable straight orbranched chain alkyl group consisting of the stated number of carbonatoms and one or two heteroatoms selected from the group consisting ofB, O, N, S, and P and wherein the nitrogen, sulfur, and phosphorousatoms may be optionally oxidized and the nitrogen heteroatom may beoptionally quaternized. The heteroatom(s) may be placed at any positionof the heteroalkyl group, including between the rest of the heteroalkylgroup and the fragment to which it is attached, as well as attached tothe most distal carbon atom in the heteroalkyl group. Examples include:—O—CH₂—CH₂—CH₃, —CH₂—CH₂—CH₂—OH, —CH₂—CH₂—NH—CH₃, —CH₂—S—CH₂—CH₃, and—CH₂CH₂—S(═O)—CH₃. Up to two heteroatoms may be consecutive, such as,for example, —CH₂—NH—OCH₃, or —CH₂—CH₂—S—S—CH₃

As used herein, the term “heteroalkenyl” by itself or in combinationwith another term means, unless otherwise stated, a stable straight orbranched chain monounsaturated or di-unsaturated hydrocarbon groupconsisting of the stated number of carbon atoms and one or twoheteroatoms selected from the group consisting of B, O, N, S, and P andwherein the nitrogen, sulfur, and phosphorous atoms may optionally beoxidized and the nitrogen heteroatom may optionally be quaternized. Upto two heteroatoms may be placed consecutively. Examples include—CH═CH—O—CH₃, —CH═CH—CH₂—OH, —CH₂—CH═N—OCH₃, —CH═CH—N(CH₃)—CH₃, and—CH₂—CH═CH—CH₂—SH.

As used herein, the term “aromatic” refers to a carbocycle orheterocycle with one or more polyunsaturated rings and having aromaticcharacter, i.e., having (4n+2) delocalized p (pi) electrons, where n isan integer.

As used herein, the term “aryl,” employed alone or in combination withother terms, means, unless otherwise stated, a carbocyclic aromaticsystem containing one or more rings (typically one, two or three rings)wherein such rings may be attached together in a pendent manner, such asa biphenyl, or may be fused, such as naphthalene. Examples includephenyl, anthracyl, and naphthyl. In one aspect, aryl includes phenyl andnaphthyl. In one aspect, the aryl is phenyl.

As used herein, the term “aryl-(C₁-C₃)alkyl” or “arylalkyl” means afunctional group wherein a one to three carbon alkylene chain isattached to an aryl group, e.g., —CH₂CH₂-phenyl or —CH₂-phenyl (benzyl).Preferred is aryl-CH₂— and aryl-CH(CH₃)—. The term “substitutedaryl-(C₁-C₃)alkyl” means an aryl-(C₁-C₃)alkyl functional group in whichthe aryl group is substituted. In one aspect, the arylalkyl issubstituted aryl(CH₂)—. Similarly, the term “heteroaryl-(C₁-C₃)alkyl”means a functional group wherein a one to three carbon alkylene chain isattached to a heteroaryl group, e.g., —CH₂CH₂-pyridyl. In one aspect,the heteroaryl-(C₁-C₃)alkyl is heteroaryl-(CH₂)—. The term “substitutedheteroaryl-(C₁-C₃)alkyl” means a heteroaryl-(C₁-C₃)alkyl functionalgroup in which the heteroaryl group is substituted. In one aspect, thesubstituted heteroaryl-(C₁-C₃)alkyl is substituted heteroaryl-(CH₂)—.

As used herein, the term “heterocycle” or “heterocyclyl” or“heterocyclic” by itself or as part of another substituent means, unlessotherwise stated, an unsubstituted or substituted, stable, mono- ormulti-cyclic heterocyclic ring system that consists of carbon atoms andat least one heteroatom selected from the group consisting of B, O, N,S, and P and wherein the nitrogen, sulfur, and phosphorous heteroatomsmay be optionally oxidized, and the nitrogen atom may be optionallyquaternized. The heterocyclic system may be attached, unless otherwisestated, at any heteroatom or carbon atom that affords a stablestructure. A heterocycle may be aromatic or non-aromatic in nature. Inone aspect, the heterocycle is a heteroaryl. A polycyclic heteroaryl mayinclude one or more rings that are partially saturated. Examples includethe following moieties:

As used herein, the term “heterocycloalkyl” or “heterocyclyl” refers toa heteroalicyclic group containing one to four ring heteroatoms eachselected from B, O, S, N, and P. In one aspect, each heterocycloalkylgroup has from 4 to 10 atoms in its ring system, with the proviso thatthe ring of said group does not contain two adjacent O or S atoms. Inanother aspect, the heterocycloalkyl group is fused with an aromaticring. In one aspect, the nitrogen and sulfur heteroatoms may beoptionally oxidized, and the nitrogen atom may be optionallyquaternized. The heterocyclic system may be attached, unless otherwisestated, at any heteroatom or carbon atom that affords a stablestructure. A heterocycle may be aromatic or non-aromatic in nature. Inone aspect, the heterocycle is a heteroaryl.

An example of a 3-membered heterocycloalkyl group includes, and is notlimited to, aziridine. Examples of 4-membered heterocycloalkyl groupsinclude, and are not limited to, azetidine and a beta lactam. Examplesof 5-membered heterocycloalkyl groups include, and are not limited to,pyrrolidine, oxazolidine and thiazolidinedione. Examples of 6-memberedheterocycloalkyl groups include, and are not limited to, piperidine,morpholine and piperazine.

Other non-limiting examples of heterocycloalkyl groups are:

Examples of non-aromatic heterocycles include monocyclic groups such asaziridine, oxirane, thiirane, azetidine, oxetane, thietane, pyrrolidine,pyrroline, pyrazolidine, imidazoline, dioxolane, sulfolane,2,3-dihydrofuran, 2,5-dihydrofuran, tetrahydrofuran, thiophane,piperidine, 1,2,3,6-tetrahydropyridine, 1,4-dihydropyridine, piperazine,morpholine, thiomorpholine, pyran, 2,3-dihydropyran, tetrahydropyran,1,4-dioxane, 1,3-dioxane, homopiperazine, homopiperidine, 1,3-dioxepane,4,7-dihydro-1,3-dioxepin, and hexamethyleneoxide.

As used herein, the term “heteroaryl” or “heteroaromatic” refers to aheterocycle having aromatic character. A polycyclic heteroaryl mayinclude one or more rings that are partially saturated. Examples includethe following moieties:

Examples of heteroaryl groups include pyridyl, pyrazinyl, pyrimidinyl(such as, but not limited to, 2- and 4-pyrimidinyl), pyridazinyl,thienyl, furyl, pyrrolyl, imidazolyl, thiazolyl, oxazolyl, pyrazolyl,isothiazolyl, 1,2,3-triazolyl, 1,2,4-triazolyl, 1,3,4-triazolyl,tetrazolyl, 1,2,3-thiadiazolyl, 1,2,3-oxadiazolyl, 1,3,4-thiadiazolyland 1,3,4-oxadiazolyl.

Examples of polycyclic heterocycles include indolyl (such as, but notlimited to, 3-, 4-, 5-, 6- and 7-indolyl), indolinyl, quinolyl,tetrahydroquinolyl, isoquinolyl (such as, but not limited to, 1- and5-isoquinolyl), 1,2,3,4-tetrahydroisoquinolyl, cinnolinyl, quinoxalinyl(such as, but not limited to, 2- and 5-quinoxalinyl), quinazolinyl,phthalazinyl, 1,8-naphthyridinyl, 1,4-benzodioxanyl, coumarin,dihydrocoumarin, 1,5-naphthyridinyl, benzofuryl (such as, but notlimited to, 3-, 4-, 5-, 6- and 7-benzofuryl), 2,3-dihydrobenzofuryl,1,2-benzisoxazolyl, benzothienyl (such as, but not limited to, 3-, 4-,5-, 6-, and 7-benzothienyl), benzoxazolyl, benzothiazolyl (such as, butnot limited to, 2-benzothiazolyl and 5-benzothiazolyl), purinyl,benzimidazolyl, benztriazolyl, thioxanthinyl, carbazolyl, carbolinyl,acridinyl, pyrrolizidinyl, and quinolizidinyl.

The aforementioned listing of heterocyclyl and heteroaryl moieties isintended to be representative and not limiting.

As used herein, the term “substituted” means that an atom or group ofatoms has replaced hydrogen as the substituent attached to anothergroup. The term “substituted” further refers to any level ofsubstitution, namely mono-, di-, tri-, tetra-, or penta-substitution,where such substitution is permitted. The substituents are independentlyselected, and substitution may be at any chemically accessible position.In one aspect, the substituents vary in number between one and four. Inanother aspect, the substituents vary in number between one and three.In yet another aspect, the substituents vary in number between one andtwo.

As used herein, the term “optionally substituted” means that thereferenced group may be substituted or unsubstituted. In one aspect, thereferenced group is optionally substituted with zero substituents, i.e.,the referenced group is unsubstituted. In another aspect, the referencedgroup is optionally substituted with one or more additional group(s)individually and independently selected from groups described herein.

In one aspect, the substituents are independently selected from thegroup consisting of oxo, halogen, —CN, —NH₂, —OH, —NH(CH₃), —N(CH₃)₂,alkyl (including straight chain, branched and/or unsaturated alkyl),substituted or unsubstituted cycloalkyl, substituted or unsubstitutedheterocycloalkyl, fluoro alkyl, substituted or unsubstitutedheteroalkyl, substituted or unsubstituted alkoxy, fluoroalkoxy,—S-alkyl, S(═O)₂alkyl, —C(═O)NH[substituted or unsubstituted alkyl, orsubstituted or unsubstituted phenyl], —C(═O)N[H or alkyl]₂,—OC(═O)N[substituted or unsubstituted alkyl]₂, —NHC(═O)NH[substituted orunsubstituted alkyl, or substituted or unsubstituted phenyl],—NHC(═O)alkyl, —N[substituted or unsubstituted alkyl]C(═O)[substitutedor unsubstituted alkyl], —NHC(═O)[substituted or unsubstituted alkyl],—C(OH)[substituted or unsubstituted alkyl]₂, and —C(NH₂)[substituted orunsubstituted alkyl]₂. In one aspect, by way of example, an optionalsubstituent is selected from oxo, fluorine, chlorine, bromine, iodine,—CN, —NH₂, —OH, —NH(CH₃), —N(CH₃)₂, —CH₃, —CH₂CH₃, —CH(CH₃)₂, —CF₃,—CH₂CF₃, —OCH₃, —OCH₂CH₃, —OCH(CH₃)₂, —OCF₃, —OCH₂CF₃, —S(═O)₂—CH₃,—SO₃H, —C(═O)NH₂, —C(═O)—NHCH₃, —NHC(═O)NHCH₃, —C(═O)CH₃, and —C(═O)OH.In one aspect, the substituents are independently selected from thegroup consisting of C₁₋₆ alkyl, —OH, C₁₋₆ alkoxy, halo, amino,acetamido, oxo and nitro. In yet another aspect, the substituents areindependently selected from the group consisting of C₁₋₆ alkyl, C₁₋₆alkoxy, halo, acetamido, and nitro. As used herein, where a substituentis an alkyl or alkoxy group, the carbon chain may be branched, straightor cyclic, with straight being preferred. In one aspect, thesubstituents are positively or negatively charged groups consisting of—NR₃ ⁺, —SO₃ ⁻, or related species.

For aryl, aryl-(C₁-C₃)alkyl and heterocyclyl groups, the term“substituted” as applied to the rings of these groups refers to anylevel of substitution, namely mono-, di-, tri-, tetra-, orpenta-substitution, where such substitution is permitted. Thesubstituents are independently selected, and substitution may be at anychemically accessible position. In one aspect, the substituents vary innumber between one and four. In one aspect, the substituents vary innumber between one and three. In one aspect, the substituents vary innumber between one and two.

As used herein, the terms “DPPBz,” “DEPBz,” “dppe,” and “depe” refer tothe structures shown by the formulas as follows:

In the foregoing, “Ph” refers to a phenyl group, and “Et” refers to anethyl group. That is, “Ph” represents the structure shown by thefollowing formula:

and“Et” represents the structure shown by the following formula:

Unless otherwise specified, temperatures referred to herein are based onatmospheric pressure (i.e. one atmosphere).

In various aspects, the present disclosure relates in part to highlyactive cationic cobalt phosphine complexes, both mono- and bimetallic,that can catalyze hydroformylation reactions. The disclosed catalystscan be utilized in methods that provide reaction processes that arehundreds of times faster than high pressure HCo(CO)₄ orphosphine-modified HCo(CO)₃(PR₃) catalysts and operate at considerablylower pressures and temperatures.

Thus, the present disclosure is related in part to methods ofhydroformylation.

Compounds of the Disclosure.

The compounds of the present disclosure may be synthesized usingtechniques well-known in the art of organic synthesis. The startingmaterials and intermediates required for the synthesis may be obtainedfrom commercial sources or synthesized according to methods known tothose skilled in the art.

In various aspects, the present disclosure relates to a compound offormula I, or a salt, solvate, or stereoisomer thereof:

wherein in formula I: X is selected from the group consisting of O, NR⁸,and CR⁹R¹⁰, wherein R⁸, R⁹, and R¹⁰ can be the same or different and areeach independently selected from the group consisting of H, C₁-C₅ alkyl,C₂-C₅ alkenyl, C₁-C₅ alkoxy, C₁-C₂₀ alcohol, C₃-C₆cycloalkyl, C₃-C₆cycloalkoxy, C₆-C₁₀ aryl, C₆-C₁₀ alkaryl, C₆-C₁₀ aralkyl, C₄-C₁₀heteroaryl, and combinations thereof; or optionally R⁹ and R¹⁰ cantogether form a C₃-C₆ cycloalkyl ring; each occurrence of Yindependently represents a divalent linking group selected from thegroup consisting of C₁-C₆ alkyl, C₁-C₆ alkenyl, C₆-C₁₄ aryl, C₄-C₁₄heteroaryl, O, NR⁴, and combinations thereof; each occurrence of R¹, R²,R³, and R⁴ is independently selected from the group consisting of C₁-C₂₀alkyl, C₁-C₈ alkoxy, C₁-C₂₀ alcohol, C₃-C₆cycloalkyl, C₃-C₆ cycloalkoxy,C₆-C₁₀ aryl, C₆-C₁₀ alkaryl, C₆-C₁₀ aralkyl, C₄-C₁₀ heteroaryl, andcombinations thereof; or R² and R³ may optionally be joined together toform a ring; or optionally one of R¹ and one of either R⁹ or R¹⁰ maytogether form a ring; M¹ and M² each independently represent atransition metal selected from the group consisting of Fe, Co, Ni, Cu,Ru, Rh, Pd, Ir, and Pt, and M¹ and M² can be the same or different; n isan integer between 0 and 4, wherein the value of the number n for theligand L¹ depends on the transition metal M¹ and is selected such thatthe transition metal M¹ has 14, 15, 16, 17, 18, or 19 valence electrons;m is an integer between 0 and 4, wherein the value of the number m forthe ligand L² depends on the transition metal M² and is selected suchthat the transition metal M² has 14, 15, 16, 17, 18, or 19 valenceelectrons; p is an integer between 0 and 4; and L¹ and L² can be thesame or different and each occurrence is independently selected from thegroup consisting of trialkylphosphine, tricycloalkylphosphine, diethylether, tetrahydrofuran, H₂O, CO, acetylacetonate, acetate, C₁-C₈alkoxide, acetonitrile, cyclooctadiene, N(R¹¹)₃, N(R¹¹)₂, C₁-C₆ alkyl,C₄-C₁₀ heteroaryl, C₄-C₁₀ heterocycle, H, Cl, Br, I, and F; wherein R¹¹is H, alkyl, cyclcoalkyl, heteroalkyl, or heterocyclic.

In a further aspect, X is CR⁹R¹⁰. In one aspect, R⁹ and R¹⁰ are eachhydrogen. In one aspect, R² and R³ are each C₁-C₅ alkyl. In one aspect,R² and R³ are each ethyl. In one aspect, R¹ is phenyl. In one aspect, Yis 1,2-phenylene, which is optionally substituted. In one aspect, M¹ andM² are each independently selected from the group consisting of Co andRh. In one aspect, p is 2. In one aspect, L¹ and L² are eachindependently selected from the group consisting of acetoacetonate,acetonitrile, pyridine, and cyclooctadiene.

In a still further aspect, X is selected from NR⁸ and CR⁹R¹⁰, whereineach of R⁸, R⁹, and R¹⁰ is independently selected from the groupconsisting of H, C₁-C₁₂ alkyl, C₁-C₂₀ alcohol, C₃-C₆cycloalkyl, C₆-C₁₀aryl, and C₆-C₁₀ alkyl-substituted aryl (with C₁-C₁₂ alkyls), andwherein R⁹ and R¹⁰ can form a C₃-C₆ cycloalkyl ring. In a yet furtheraspect, X is selected from NR⁸ and CR⁹R¹⁰, wherein each of R⁸, R⁹, andR¹⁰ is independently selected from the group consisting of H, C₄-C₁₂alkyl, C₄-C₁₂ alcohol, C₆ cycloalkyl, C₈-C₁₀ aryl, and C₈-C₁₀alkyl-substituted aryl (with C₁-C₆ alkyls), and wherein R⁹ and R¹⁰ canform a C₅-C₆ cycloalkyl ring.

In a further aspect, X is selected from C₈-C₁₀ aryl and C₈-C₁₀alkyl-substituted aryl (with C₁-C₁₂ alkyls).

In a further aspect, Y is selected from C₂-C₆ alkyl, C₂-C₆ alkenyl,C₆-C₁₀ aryl, and C₆-C₁₀ alkyl-substituted aryl (with C₁-C₁₂ alkyls). Ina still further aspect, Y is selected from C₂-C₃ alkyl, C₂-C₄ alkenyl,C₆-C₁₀ aryl, and C₆-C₁₀ alkyl-substituted aryl (with C₁-C₆ alkyls). In ayet further aspect, Y is selected from C₆-C₁₀ aryl and C₈-C₁₀alkyl-substituted aryl (with C₁-C₁₂ alkyls).

In a further aspect, each of R¹, R², R³, and R⁴ is independentlyselected from the group consisting of C₁-C₁₂ alkyl, C₁-C₂₀ alcohol,C₃-C₆ cycloalkyl, C₆-C₁₀ aryl, and C₆-C₁₀ alkyl-substituted aryl (withC₁-C₁₂ alkyls); or R² and R³ may optionally be joined together to form aring. In a still further aspect, each of R¹, R², R³, and R⁴ isindependently selected from the group consisting C₂-C₈ alkyl, C₂-C₁₀alcohol, C₅-C₆ cycloalkyl, C₆-C₁₀ aryl, C₆-C₁₀ alkyl-substituted aryl(with C₁-C₆ alkyls), and combinations thereof; or R² and R³ mayoptionally be joined together to form a ring.

In a further aspect, each of M¹ and M² are independently are atransition metal selected from the group consisting of Fe, Co, Ni, Ru,Rh, and Pd, wherein M¹ and M² can be the same or different. In someaspects, each of M¹ and M² are different. For example, each of M¹ and M²are independently are a transition metal selected from the groupconsisting of Fe, Ni, Co, Ru, Rh, and Pd, such that M¹ and M² aredifferent transition metals. In other aspects, each of each of M¹ and M²are the same. For example, each of M¹ and M² are the same transitionmetal selected from the group consisting of Fe, Ni, Co, Ru, Rh, and Pd.In a still further aspect, each of M¹ and M² are independently are atransition metal selected from the group consisting of Fe, Co, Ru, Rh,and Pd, and M¹ and M² can be the same or different. In some aspects,each of M¹ and M² are different. For example, each of M¹ and M² areindependently are a transition metal selected from the group consistingof Fe, Co, Ru, Rh, and Pd, such that M¹ and M² are different transitionmetals. In other aspects, each of each of M¹ and M² are the same. Forexample, each of M¹ and M² are the same transition metal selected fromthe group consisting of Fe, Co, Ru, Rh, and Pd. In a yet further aspect,each of M¹ and M² is Co.

In a further aspect, for each occurrence of L¹ and L² is independentlyselected from the group consisting of trialkylphosphine,tetrahydrofuran, H₂O, CO, acetylacetonate, C₁-C₆ alkoxide, acetonitrile,cyclooctadiene, N(R¹¹)₃, N(R¹¹)₂, C₁-C₆ alkyl, C₄-C₁₀ heteroaryl, C₄-C₁₀heterocycle, H, Cl, Br, I, and F; wherein R¹¹ is H, alkyl, cyclcoalkyl,heteroalkyl, and heterocyclic, wherein each occurrence of L¹ and L² bethe same or different. In a still further aspect, for each occurrence ofL¹ and L² is independently selected from the group consisting oftetrahydrofuran, H₂O, CO, acetylacetonate, C₁-C₆ alkoxide, acetonitrile,N(R¹¹)₂, C₁-C₆ alkyl, H, Cl, Br, I, and F; wherein R¹¹ is H, alkyl,cyclcoalkyl, heteroalkyl, and heterocyclic, wherein each occurrence ofL¹ and L² be the same or different.

In a further aspect, the compound of formula I is selected from thegroup consisting of:

In various aspects, the present disclosure relates to a compound offormula (II), or a salt, solvate, or stereoisomer thereof:

wherein in formula (II): each occurrence of R⁵ and R⁶ is independentlyselected from the group consisting of C₁-C₂₀ alkyl, C₁-C₈ alkoxy, C₁-C₂₀alcohol, C₃-C₆ cycloalkyl, C₃-C₆ cycloalkoxy, C₆-C₁₀ aryl, C₆-C₁₀alkaryl, C₆-C₁₀ aralkyl, or combinations thereof; or R⁵ and R⁶ mayoptionally be joined together to form a ring; Z represents a divalentlinking group selected from the group consisting of C₁-C₆ alkyl, C₁-C₆alkenyl, C₆-C₁₄ aryl, C₄-C₁₄ heteroaryl, O, NR⁴, and combinationsthereof; M is a transition metal selected from the group consisting ofFe, Co, Ni, Cu, Ru, Rh, Pd, Ir, and Pt; o is an integer between 0 and 4,wherein the value of the number o for the ligand L depends on thetransition metal M and is selected such that the transition metal M has14, 15, 16, 17, 18, or 19 valence electrons; q is an integer between 0and 4; and each occurrence of L can be the same or different and isselected from the group consisting of trialkylphosphine,tricycloalkylphosphine, diethyl ether, tetrahydrofuran, H₂O, CO,acetylacetonate, acetate, C₁-C₆ alkoxide, acetonitrile, cyclooctadiene,N(R¹¹)₃, N(R¹¹)₂, C₁-C₆ alkyl, C₄-C₁₀ heteroaryl, C₄-C₁₀ heterocycle, H,Cl, Br, I, and F; wherein R¹¹ is H, alkyl, cyclcoalkyl, heteroalkyl, orheterocyclic.

In a further aspect, o is an integer between 1 and 3, wherein the valueof the number o for the ligand L depends on the transition metal M andis selected such that the transition metal M has 15, 16, 17, 18, or 19valence electrons. In a still further aspect, o is an integer between 2and 3, wherein the value of the number o for the ligand L depends on thetransition metal M and is selected such that the transition metal M has15, 16, 17, 18, or 19 valence electrons.

In a further aspect, q is an integer selected from 0, 1, 2, and 3. In astill further aspect, q is an integer selected from 0, 1, and 2.

In a further aspect, the compound of formula (II) is selected from thegroup consisting of:

In a further aspect, each occurrence of R⁵ and R⁶ is independentlyselected from the group consisting of C₁-C₁₃ alkyl, C₁-C₂₀ alcohol,C₃-C₆ cycloalkyl, C₆-C₁₀ aryl, and C₆-C₁₀ alkyl-substituted aryl (withC₁-C₁₂ alkyls); and wherein R⁵ and R⁶ may optionally be joined togetherto form a ring. In a still further aspect, each occurrence of R⁵ and R⁶is independently selected from the group consisting of C₂-C₁₂ alkyl,C₁-C₁₂ alcohol, C₅-C₆ cycloalkyl, C₆-C₁₀ aryl, C₆-C₁₀ alkyl-substitutedaryl (with C₁-C₆ alkyls), or combinations thereof; or wherein R⁵ and R⁶may optionally be joined together to form a ring. In a yet furtheraspect, each occurrence of R⁵ and R⁶ is independently selected from aC₆-C₁₀ alkyl-substituted aryl (with C₁-C₆ alkyls). In a still furtheraspect, R⁵ and R⁶ are each C₁-C₆ alkyl, phenyl, or cycloalkyl, each ofwhich may be optionally substituted.

In a further aspect, Z is a divalent linking group selected from thegroup consisting of C₂-C₄ alkyl, C₂-C₆ alkenyl, C₆-C₁₄ aryl, andcombinations thereof. In a still further aspect, Z is a divalent linkinggroup selected from the group consisting of C₂-C₃ alkyl, C₂-C₄ alkenyl,C₆-C₁₄aryl, and combinations thereof. In a yet further aspect, Z is1,2-phenylene, 1,2-ethylene, or 1,3-propylene.

In a further aspect, M is a transition metal selected from the groupconsisting of Fe, Co, Ni, Ru, Rh, Pd, and Ir. In a still further aspect,M is a transition metal selected from the group consisting of Fe, Co,Ru, Rh, and Pd. In a yet further aspect, M is Co. In a further aspect, Mis Rh or Co.

In a further aspect, each occurrence of L can be the same or differentand each occurrence is independently selected from the group consistingof trialkylphosphine, tetrahydrofuran, H₂O, CO, acetylacetonate, C₁-C₆alkoxide, acetonitrile, cyclooctadiene, N(R¹¹)₃, N(R¹¹)₂, C₁-C₆ alkyl,C₄-C₁₀ heteroaryl, C₄-C₁₀ heterocycle, H, Cl, Br, I, and F; wherein R¹¹is H, alkyl, cyclcoalkyl, heteroalkyl, or heterocyclic. In a stillfurther aspect, each occurrence of L can be the same or different andeach occurrence is independently selected from the group consisting oftetrahydrofuran, H₂O, CO, acetylacetonate, C₁-C₆ alkoxide, acetonitrile,N(R¹¹)₂, C₁-C₆ alkyl, H, Cl, Br, I, and F; wherein R¹¹ is H, alkyl,cyclcoalkyl, heteroalkyl, or heterocyclic.

In a further aspect, one or more occurrence of L, L¹, or L² represents aneutral electron donor ligand. Non-limiting examples of suitable ligandsinclude those containing an atom, such as oxygen, nitrogen, phosphorousor sulfur, which has a non-bonded electron pair. Examples of suchligands include, but are not limited to, ethers, amines, phosphines, andthioethers. In one aspect, the electron donor ligand is atricycloalkyl-, triaryl-, or trialkylphosphine. In one aspect, theelectron donor ligand is a solvent molecule such as tetrahydrofuran(THF), H₂O, MeOH, or EtOH. In one aspect, the electron donor ligand is aligand containing one or more π-bonds, such as alkenyl, alkynyl, aryl,and the like. In one aspect, the electron donor ligand is a heterocyclicor heteroaryl compound containing a non-bonded electron pair, as wouldbe understood by one of skill in the art. In one aspect, the electrondonor ligand is a bidentate electron donor ligand such as ethylenediamine, phenanthroline, 2,2′-bipyridine, and the like. In one aspect,the neutral electron donor ligand is a ligand that exhibits backbonding,such as CO.

In a further aspect, one or more occurrence of L, L¹, or L² representsan anionic ligand. Exemplary anionic ligands include, but are notlimited to, hydrogen, substituted or unsubstituted alkyl, halo, hydroxy,alkoxy, aryloxy, silyl, amide, phosphide, cyano, nitrite, orcombinations thereof. In one aspect, the anionic ligand is an alkylligand such as methyl, ethyl, propyl, butyl, amyl, isoamyl, hexyl,iso-butyl, heptyl, octyl, nonyl, decyl, cetyl, 2-ethylhexyl, phenyl andthe like. In one aspect, the anionic ligand is a halogen such as F, Cl,Br, or I. In one aspect, the anionic ligand is an alkoxide such asmethoxide, ethoxide, phenoxide, or substituted phenoxide. In one aspect,the anionic ligand is an amide such as dimethylamide, diethylamide,methylethylamide, di-t-butylamide, diisopropylamide, and the like. Inone aspect, the anionic ligand is a phosphide such as diphenylphosphide,dicyclohexylphosphide, diethylphosphide, dimethylphosphide and the like.In one aspect, the anionic ligand is cyclopentadienyl. In one aspect,the ligand L represents a bidentate anionic ligand such asacetylacetonate, glycinate (or other comparable amino acid), and thelike. In a still further aspect, L is acetylacetonate.

In a further aspect, one or more occurrence of L¹ or L² represents abridging ligand coordinating to both of M¹ and M². Exemplary bridgingligands include, but are not limited to, hydroxyl, alkoxyl, oxide,hydrosulfyl, sulfalkyl, amide, alkylamide, nitride, halo, hydrogen,nitrile, CO, 1,2-pyrazine, 1,3-pyrazine, 1,4-pyrazine, and the like.

In a further aspect, the divalent linking groups Y in formula (I) is1,2-phenylene. In one aspect, the divalent linking group Z in formula(II) is 1,2-phenylene. In one aspect, the divalent linking group is1,2-ethylene, 1,3-propylene, or 1,4-butylene. In one aspect, thedivalent linking group is not methylene. In one aspect, the divalentlinking group imposes a chelate upon the metal center.

In a further aspect, the substituents R², R³, R⁵, and R⁶ are selected soas to not create a steric block on the axial coordination site of themetal. In one aspect, R², R³, R⁵, and R⁶ are independently selected fromthe group consisting of linear alkyl groups, cycloalkyl groups having nosubstitution at the 2-position, and unsubstituted aryl groups or arylgroups not substituted at the 2-position. In one aspect, R² and R³, orR⁵ and R⁶, together form a ring having no additional substitution. Inone aspect, R² and/or R³ forms a bond with an atom on divalent linkinggroup Y. In one aspect, R⁵ and/or R⁶ forms a bond with an atom ondivalent linking group Z. In one aspect, a bond connecting divalentgroup Y with at least one of R² or R³, or a bond connecting divalentgroup Z with at least one of R⁵ or R⁶, further limits steric incumbencyon the axial coordination site of the metal.

In a further aspect, the compound of formula I or the compound offormula (II) further comprises a weakly coordinating anion, which may beany suitable anion known for this purpose, as would be understood by oneof ordinary skill in the art. In one aspect, the weakly coordinationanion is a bulky anion or an anion with a delocalized negative charge.Exemplary weakly coordinating anions include, but are not limited to,tetrakis [3,5-bis(trifluoromethyl)phenyl]borate (herein referred to asBArF⁻), (phenyl)₄B⁻, (C₆F⁵)₄B⁻, (CH₃)(C₆F₅)₃B⁻, PF⁻, BF₄ ⁻, SbF₆ ⁻,trifluoromethanesulfonate (herein referred to as triflate or OTf⁻), andp-toluenesulfonate (herein referred to as tosylate or OTs⁻).

In a further aspect, the ligands L, L¹, and L² and the integers n, m, o,p, and q are selected in order to control the number of electrons on thetransition metal M. In one aspect, the number of electrons on thetransition metal M is 14, 15, 16, 17, 18, or 19, depending on theapplication of the compound or the reaction conditions, as would beunderstood by one of skill in the art. In one aspect, p is 1, 2, 3, or4. In one aspect, p is 2 or 4. In one aspect, q is 1 or 2. In oneaspect, q is 1. In one aspect, a localized cationic charge of +1 to +3on the metal center is important for high catalyst activity.

The compounds of the disclosure may possess one or more stereocenters,and each stereocenter may exist independently in either the R or Sconfiguration. In one aspect, compounds described herein are present inoptically active, racemic, or meso diastereomeric forms. It is to beunderstood that the compounds described herein encompass racemic,optically-active, regioisomeric and stereoisomeric forms, orcombinations thereof that possess the catalytically useful propertiesdescribed herein. Preparation of optically active forms is achieved inany suitable manner, including by way of non-limiting example, byresolution of the racemic form with recrystallization techniques,synthesis from optically-active starting materials, chiral synthesis, orchromatographic separation using a chiral stationary phase. In oneaspect, a mixture of one or more isomer is utilized as the compounddescribed herein. In another aspect, compounds described herein containone or more chiral centers. These compounds are prepared by any means,including stereoselective synthesis, enantioselective synthesis and/orseparation of a mixture of enantiomers and/or diastereomers. Resolutionof compounds and isomers thereof is achieved by any means including, byway of non-limiting example, chemical processes, enzymatic processes,fractional crystallization, distillation, and chromatography.

The methods and formulations described herein include the use ofN-oxides (if appropriate), crystalline forms (also known as polymorphs),solvates, amorphous phases, and/or salts of compounds having thestructure of any compound of the disclosure, as well as analogs of thesecompounds having the same type of activity. Solvates include water,ether (e.g., tetrahydrofuran, methyl tert-butyl ether, dioxane) oralcohol (e.g., ethanol) solvates, acetates and the like. In one aspect,the compounds described herein exist in solvated forms with solventssuch as water, diethyl ether, tetrahydrofuran, dioxane, and ethanol. Inanother aspect, the compounds described herein exist in unsolvated form.

In one aspect, the compounds of the disclosure may exist as tautomers.All tautomers are included within the scope of the compounds presentedherein.

The compounds described herein, and other related compounds havingdifferent substituents are synthesized using techniques and materialsdescribed, for example, in Fieser & Fieser's Reagents for OrganicSynthesis, Volumes 1-17 (John Wiley and Sons, 1991); Rodd's Chemistry ofCarbon Compounds, Volumes 1-5 and Supplementals (Elsevier SciencePublishers, 1989); Organic Reactions, Volumes 1-40 (John Wiley and Sons,1991), Larock's Comprehensive Organic Transformations (VCH PublishersInc., 1989), March, Advanced Organic Chemistry 4^(th) Ed., (Wiley 1992);Carey & Sundberg, Advanced Organic Chemistry 4th Ed., Vols. A and B(Plenum 2000, 2001), and Green & Wuts, Protective Groups in OrganicSynthesis 3rd Ed., (Wiley 1999) (all of which are incorporated byreference for such disclosure). General methods for the preparation ofcompound described herein are modified by the use of appropriatereagents and conditions, for the introduction of the various moietiesfound in the formula as provided herein.

Compounds described herein are synthesized using any suitable proceduresstarting from compounds that are available from commercial sources.

In one aspect, reactive functional groups, such as hydroxyl, amino,imino, thio or carboxy groups, can be protected in order to avoid theirunwanted participation in reactions. Protecting groups are used to blocksome or all of the reactive moieties and prevent such groups fromparticipating in chemical reactions until the protective group isremoved. In another aspect, each protective group is removable by adifferent means. Protective groups that are cleaved under totallydisparate reaction conditions fulfill the requirement of differentialremoval.

In one aspect, protective groups are removed by acid, base, reducingconditions (such as, for example, hydrogenolysis), and/or oxidativeconditions. Groups such as trityl, dimethoxytrityl, acetal andt-butyldimethylsilyl are acid labile and are used to protect carboxy andhydroxy reactive moieties in the presence of amino groups protected withCbz groups, which are removable by hydrogenolysis, and Fmoc groups,which are base labile. Carboxylic acid and hydroxy reactive moieties areblocked with base labile groups such as, but not limited to, methyl,ethyl, and acetyl, in the presence of amines that are blocked with acidlabile groups, such as t-butyl carbamate, or with carbamates that areboth acid and base stable but hydrolytically removable.

In one aspect, carboxylic acid and hydroxy reactive moieties are blockedwith hydrolytically removable protective groups such as the benzylgroup, while amine groups capable of hydrogen bonding with acids areblocked with base labile groups such as Fmoc. Carboxylic acid reactivemoieties are protected by conversion to simple ester compounds asexemplified herein, which include conversion to alkyl esters, or areblocked with oxidatively-removable protective groups such as2,4-dimethoxybenzyl, while co-existing amino groups are blocked withfluoride labile silyl carbamates.

Allyl blocking groups are useful in the presence of acid- andbase-protecting groups since the former are stable and are subsequentlyremoved by metal or pi-acid catalysts. For example, an allyl-blockedcarboxylic acid is deprotected with a palladium-catalyzed reaction inthe presence of acid labile t-butyl carbamate or base-labile acetateamine protecting groups.

Yet another form of protecting group is a resin to which a compound orintermediate is attached. As long as the residue is attached to theresin, that functional group is blocked and does not react. Oncereleased from the resin, the functional group is available to react.

Typically blocking/protecting groups may be selected from:

Other protecting groups, plus a detailed description of techniquesapplicable to the creation of protecting groups and their removal aredescribed in Greene & Wuts, Protective Groups in Organic Synthesis, 3rdEd., John Wiley & Sons, New York, N.Y., 1999, and Kocienski, ProtectiveGroups, Thieme Verlag, New York, N.Y., 1994, which are incorporatedherein by reference for such disclosure.

The compounds described herein may form salts with acids or bases, andsuch salts are included in the present disclosure. The term “salts”embraces addition salts of free acids or free basis that are usefulwithin the methods of the disclosure. Salts may possess properties suchas high crystallinity, which have utility in the practice of the presentdisclosure, such as for example utility in process of synthesis orpurification of compounds useful within the methods of the disclosure.

Suitable salts may be prepared from an inorganic acid or from an organicacid. Examples of inorganic acids include perchlorate, hydrochloric,hydrobromic, hydriodic, nitric, carbonic, sulfuric, and phosphoricacids. Appropriate organic acids may be selected from aliphatic,cycloaliphatic, aromatic, araliphatic, heterocyclic, carboxylic andsulfonic classes of organic acids, examples of which include formic,acetic, propionic, succinic, glycolic, gluconic, lactic, malic,tartaric, dibenzoyltartaric, dibenzyltartaric, benzoyltartaric,benzyltartaric, citric, ascorbic, glucuronic, maleic, fumaric, pyruvic,aspartic, glutamic, benzoic, anthranilic, 4-hydroxybenzoic,phenylacetic, mandelic, embonic (pamoic), methanesulfonic,ethanesulfonic, benzenesulfonic, pantothenic, trifluoromethanesulfonic,2-hydroxyethanesulfonic, p-toluenesulfonic, sulfanilic,cyclohexylaminosulfonic, stearic, alginic, p-hydroxybutyric, salicylic,galactaric and galacturonic acid.

Methods of the Disclosure

The disclosure also includes methods hydroformylation. The methods maybe performed using compounds described herein. As would be understood byone of ordinary skill in the art, the compounds described herein areuseful as catalysts in the methods and reactions of the presentdisclosure. In one aspect, the disclosure includes isomerization ofalkenes by movement of the double bond to other locations. In anotheraspect, the disclosure includes hydrogenation of aldehydes to formalcohols.

In one aspect, the present disclosure relates to a method of preparingan aldehyde-containing compound. In one aspect, the method includescontacting an alkene-containing compound with a compound of thedisclosure in the presence of hydrogen (H₂) and carbon monoxide (CO),whereby the alkene is converted to an aldehyde. In one aspect, thecompound of the disclosure is a catalyst. In one aspect, the compound ofthe disclosure is a homogenous catalyst. In one aspect, the catalyst ishighly active. In one aspect, the alkene-containing compound iscontacted with the compound of the disclosure in a chemical reaction.

In one aspect, the methods of this disclosure contemplate using thehighly active catalysts of the present disclosure for convertingalkene-containing compounds to aldehydes, in some cases with highlinear:branched (L:B) selectivity, by reacting the alkene-containingcompounds with a compound of the disclosure in the presence of H₂ andCO. In one aspect, the reaction occurs in a homogeneous reaction phase.In one aspect, the catalyst or a catalyst precursor is introduced intoan autoclave or reaction vessel dissolved in a liquid medium, orslurried, or otherwise dispersed in a liquid medium to eventuallyprovide a homogeneous reaction phase. Suitable solvents are, e.g.,alcohols, ethers, ketones, paraffins, cycloparaffins, aromatichydrocarbons, and the like. In one aspect, the solvent comprises water.In one aspect, the solvent comprises acetone. In one aspect, the solventcomprises acetonitrile. In one aspect, the solvent comprisesdimethoxytetraethylene glycol (t-glyme). In one aspect the solventcomprises propylene carbonate. In one aspect the solvent compriseswater. In one aspect the solvent comprises a water-acetone mixture. Inone aspect, the water-acetone mixture includes 10 to 50% water byvolume.

In one aspect, the compounds of the present disclosure arepre-catalysts. In one aspect, the compounds of the present disclosureare converted to active catalysts upon exposure to reaction conditions.In one aspect, the compounds of the present disclosure are converted toactive catalysts upon exposure to CO and/or H₂.

In one aspect, the alkene-containing compound comprises alkenes such asalpha olefins (i.e., olefins unsaturated in the 1-position),particularly straight chain alpha olefins having from 2 to about 20carbon atoms (C₂-C₂₀). In one aspect, the straight chain alpha olefinshave from 2 to 12 carbon atoms (C₂-C₁₂). Alpha olefins are characterizedby a terminal double bond, i.e., CH₂═CH—R. In some aspects, the alphaolefins may be substituted if the substituents do not interfere in thehydroformylation reaction. Exemplary substituents include carbonyl,carbonyloxy, oxy, hydroxy, alkoxy, phenyl and the like. Exemplary alphaolefins, include alkenes, alkyl alkenoates, alkenyl alkyl ethers,alkenols, and the like, e.g., ethylene, propene, 1-butene, 1-pentene,1-hexene, 1-heptene, 1-octene, vinyl acetate, allyl alcohol, and thelike. In one aspect, the alkene-containing compound comprises more thanone alkene compound. In one aspect, the alkene-containing compoundcomprises more than one alkene functional group. In one aspect, thealkene-containing compound has at least one branching group within 1, 2,3, or 4 carbon atoms from the terminal alkene.

In one aspect, the alkene-containing compound comprises internal doublebonds (i.e., internal alkene). In one aspect, there are no branchesbetween the internal alkene and at least one terminal position of thecompound. In one aspect, the catalysts of the present disclosureisomerize the internal alkene into a terminal alkene. In one aspect, thecatalysts of the present disclosure hydroformylate the isomerizedterminal alkene.

In one aspect, at least one reactant comprises an alkyne, including, butnot limited to alkyl, carbonyl, carbonyloxy, oxy, hydroxy, alkoxy, orphenyl alkynes. In one aspect, the hydroformylation of an alkynegenerates an α,β-unsaturated aldehyde.

In one aspect, the alkene-containing compound is contacted with thecatalyst at temperature and pressure sufficient to convert the alkene toan aldehyde, as would be understood by one of ordinary skill in the art.In one aspect, the temperature of the reaction ranges from about 50° C.to about 200° C. In one aspect, the temperature of the reaction rangesfrom about 60° C. to about 180° C. In one aspect, the temperature of thereaction ranges from about 80° C. to about 160° C. In one aspect, thetemperature of the reaction ranges from about 100° C. to about 160° C.In one aspect, the temperature of the reaction ranges from about 120° C.to about 160° C.

In one aspect, the alkene-containing compound is contacted with thecompound of the disclosure in a reaction vessel, such as would beunderstood by one of skill in the art. In one aspect, the pressure ofthe reaction vessel ranges from about 5 bar to about 150 bar. In oneaspect, the pressure of the reaction vessel ranges from about 25 to 70bar. In one aspect, the initial turnover frequency of the catalyst ofthe present disclosure increases with increasing reaction vesselpressure.

The ratio of H₂:CO can be any ratio that is sufficient to promote theconversion of the alkene to an aldehyde, as would be understood by oneof ordinary skill in the art. In one aspect, the ratio of H₂:CO rangesfrom about 10:90 to about 90:10 volume percent. In one aspect, the ratioof H₂:CO ranges from about 40:60 to 60:40 volume percent. In one aspect,higher ratios may result in greater hydrogenation of aldehydes toalcohols.

In one aspect, the catalyst is employed in the reaction mixture inconcentrations ranging from about 10⁻⁶ M to about 10⁻² M (molar). In oneaspect, the catalyst is added to the reaction vessel as a slurry or asolution, and the reaction is pressurized and brought to the desiredoperating temperature. In one aspect, the alkene-containing compound,carbon monoxide, and hydrogen are combined in desired ratios are thenintroduced into the reaction vessel to commence the reaction. In oneaspect, alkenes that are liquids at or near room temperature (e.g.,1-hexene, 1-octene) are introduced to the reaction zone prior tocharging the H₂ and CO gases. In one aspect, the process is suited tobatch-wise operation. In another aspect, the reaction is conducted undercontinuous operation via the use of suitable apparatus such as a flowreactor.

In one aspect, the reactions using the catalyst compounds describedherein result in low to very low alkene hydrogenation side reactions. Inone aspect, the reactions using the catalyst compounds described hereinresult in high linear:branched ratios. In one aspect, the reactionsusing the catalyst compounds described herein with internal alkenes withC₁-C₆ alkyl branches located near the double bond result in highlinear:branched ratios. In one aspect, the catalyst compounds describedherein reduce aldehydes to alcohol. In one aspect, the catalystcompounds described herein convert terminal alkenes to internal(non-terminal, thermodynamically favored) alkenes. In one aspect, thecatalysts described herein do not decompose over at least 150,000turnovers. In one aspect, the catalysts are active in alkeneisomerization.

In one aspect, reactions using the catalysts described herein partiallyconvert aldehydes from hydroformylation into alcohols. In one aspect,all aldehyde products are converted to alcohols via a reductionreaction. In one aspect, the reduction of the aldehydes requires noadditional catalyst(s). In one aspect, the reduction of the aldehydes toalcohols occurs in the presence of the catalyst of the presentdisclosure. In one aspect, the reduction of the aldehyde to alcohol isnot catalyzed. In one aspect, the reduction of the aldehydes to alcoholsis improved by addition of at least one additional catalyst. In oneaspect, the at least one additional catalyst does not impact thehydroformylation reaction.

A person skilled in the art recognizes, or is able to ascertain using nomore than routine experimentation, numerous equivalents to the specificprocedures, aspects, claims, and examples described herein. Suchequivalents were considered to be within the scope of this disclosureand covered by the claims appended hereto. For example, it should beunderstood, that modifications in reaction conditions, including but notlimited to reaction times, reaction size/volume, and experimentalreagents, such as solvents, catalysts, pressures, atmosphericconditions, e.g., nitrogen atmosphere, and reducing/oxidizing agents,with art-recognized alternatives and using no more than routineexperimentation, are within the scope of the present application.

It is to be understood that wherever values and ranges are providedherein, all values and ranges encompassed by these values and ranges,are meant to be encompassed within the scope of the present disclosure.Moreover, all values that fall within these ranges, as well as the upperor lower limits of a range of values, are also contemplated by thepresent application.

From the foregoing, it will be seen that aspects herein are well adaptedto attain all the ends and objects hereinabove set forth together withother advantages which are obvious and which are inherent to thestructure.

While specific elements and steps are discussed in connection to oneanother, it is understood that any element and/or steps provided hereinis contemplated as being combinable with any other elements and/or stepsregardless of explicit provision of the same while still being withinthe scope provided herein.

It will be understood that certain features and sub-combinations are ofutility and may be employed without reference to other features andsub-combinations. This is contemplated by and is within the scope of thepresent disclosure.

Since many possible aspects may be made without departing from the scopethereof, it is to be understood that all matter herein set forth orshown in the accompanying drawings and detailed description is to beinterpreted as illustrative and not in a limiting sense.

It is also to be understood that the terminology used herein is for thepurpose of describing particular aspects only, and is not intended to belimiting. The skilled artisan will recognize many variants andadaptations of the aspects described herein. These variants andadaptations are intended to be included in the teachings of thisdisclosure and to be encompassed by the claims herein.

Now having described the aspects of the present disclosure, in general,the following Examples describe some additional aspects of the presentdisclosure. While aspects of the present disclosure are described inconnection with the following examples and the corresponding text andfigures, there is no intent to limit aspects of the present disclosureto this description. On the contrary, the intent is to cover allalternatives, modifications, and equivalents included within the spiritand scope of the present disclosure.

EXAMPLES

The disclosure is further described in detail by reference to thefollowing experimental examples. These examples are provided forpurposes of illustration only, and are not intended to be limitingunless otherwise specified. Thus, the disclosure should in no way beconstrued as being limited to the following examples, but rather, shouldbe construed to encompass any and all variations which become evident asa result of the teaching provided herein.

Without further description, it is believed that one of ordinary skillin the art can, using the preceding description and the followingillustrative examples, make and utilize the compounds of the presentdisclosure and practice the claimed methods. The following workingexamples therefore, specifically point out the preferred aspects of thepresent disclosure, and are not to be construed as limiting in any waythe remainder of the disclosure.

Example 1: Cobalt Hydroformylation of 1-Alkenes

Cationic monometallic and bimetallic bis(phosphine)-chelated cobaltcatalysts that perform hydroformylation under far lower temperatures andpressures than known systems using neutral cobalt catalysts, and withfar higher activities, have been identified and are described herein. Anexemplary hydroformylation reaction is shown in FIG. 1. The catalysts ofthe present disclosure are also active in alkene isomerization withlittle alkene hydrogenation observed, which is desirable for currentprocesses. The catalysts partially convert aldehydes generated fromhydroformylation into desired alcohol products in the presence ofhydrogen. Though linear to branched (L:B) regioselectivities of 0.8:1 to1.4:1 were observed in the aldehyde products derived from 1-alkenes, thechelating bisphosphine ligand may be modified to yield higher aldehydeL:B ratios with 1-alkenes.

The development of dicationic dicobalt catalysts are based on thestronger coordinating tetraphosphine ligands, rac- andmeso-(Et₂P)(1,2-C₆H₄)P(Ph)CH₂P(Ph)(1,2-C₆H₄)(PEt₂), et,ph-P4-Ph. Thesynthesis and characterization of this ligand has been reported.(Schreiter, et al., Inorg. Chem., 2014, 53, 10036-10038). The discloseddicobalt complexes rac- and meso-[Co₂(acac)₂(et,ph-P4-Ph)](BF₄)₂ aredescribed herein. The monometallic version of the dicobalt catalyst,[Co(acac){(PEt₂)₂(1,2-C₆H₄)}](BF₄), is more active than the bimetallicsystem, particularly on a per-cobalt atom basis. Structural drawings ofthe rac-Co₂ complex and monometallic precursor complexes studied areshown in FIG. 2. These complexes generate far more activehydroformylation catalysts that operate under milder conditions relativeto the known monometallic cobalt catalysts currently in use.

The cationic cobalt bisphosphine chelated catalysts described hereinoperate between 120 and 160° C. with H₂/CO pressures of 25 to 85 bar forliquid alkenes. The catalyst appears to run about 100 to 1000 timesfaster than a model Shell catalyst that has been tested under Shellconditions (180-190° C., 65 bar, 23 mM or 2000 ppm Co, P(n-Bu)₃,P:Co=1.3:1). Unlike the Shell catalyst, the catalysts described hereinresult in low linear to branched (L:B) regioselectivities (around 1:1)with 1-alkenes like 1-hexene. The catalysts described herein are alsoactive at alkene isomerization, similar to the commercial HCo(CO)₄ andHCo(CO)₃(PR₃) catalysts. The catalysts also can partially hydrogenatealdehydes to alcohols, a process that is still under investigation.Notably, the mild reaction conditions used herein, when applied to theunchelated complex HCo(CO)₄ generated from CO₂(CO)₈, results indecomposition to cobalt metal. The catalysts described herein can beused with low catalyst loadings without sacrificing activity, unlike theShell catalyst, which requires fairly high cobalt and phosphineconcentrations in order to form the proper active catalyst equilibrium.The catalysts described herein have been used with 0.0001% catalystloading (0.006 mM or 6 μM) and did 179,000 turnovers over 41 hours withno sign of catalyst decomposition.

The results from several hydroformylation runs using[Co(acac){(Et₂P)₂-1,2-C₆H₄)}](BF₄) and 1-hexene at different pressuresis shown in Table 1.

TABLE 1 Pressure Effect in Hydroformylation of 1-Hexene using[Co(acac){(Et₂P)₂-1,2-C₆H₄)}](BF₄) at 160° C. (1M 1-hexene, 1 mM Co, 1:1H₂/CO, t-glyme solvent). Initial Pressure TOF % % % % (bar) Time (min⁻¹)L:B Aldehyde Alcohol iso* hydro* 27.6 10 min 26.8 26.8 0 62.6 0.8  2 hr0.92 67.2 4.7 25.3 1.9 34.5 10 min 31.4 31.4 0 56.1 0.8  2 hr 0.97 78.26.0 13.5 1.8 51.7 10 min 42.0 42.0 0 38.0 0.8  2 hr 1.1 85.5 6.0 6.7 1.468.9 10 min 46.8 46.8 0 29.8 0.8  2 hr 1.3 87.9 4.4 6.2 1.3 *iso =alkene isomerization; hydro = alkene hydrogenation

Example 2: Cobalt Hydroformylation of Internal Branched Alkenes

The cationic cobalt catalysts described herein have excellent activityand much higher L:B selectivity for difficult to hydroformylate internalbranched alkenes like 2-methyl-2-butene. Hydroformylation runs with2-methyl-2-butene were done with [Co(acac)(dppe)](BF₄),dppe=Et₂PCH₂CH₂PEt₂, and Rh(acac)(CO)₂+PPh₃. The following reactionconditions were utilized: (a) HRh(CO)(PPh₃)₂: 1 mM Rh(acac)(CO)₂, 0.4 MPPh₃, 400:1 PPh₃:Rh, 1 M 2-methyl-2-butene, 100° C., 7.9 bar, 1:1 H₂/COin toluene; and (b) [HCo(CO)(dppe)](BF₄): 1 mM [Co(acac)(dppe)](BF₄), 1M 2-methyl-2-butene, 140° C., 34.5 bar, 1:1 H₂/CO in t-glyme. Using theforegoing, it was observed that there was no hydroformylation activityby the industrial Rh/PPh₃ catalyst, no observed alkene isomerization andno alkene hydrogenation. The cationic cobalt-dppe catalyst did 286turnovers after 3 hours (28.6% conversion) with 11:1 L:B (based on NMRand GC/MS). Less than 1% alkene hydrogenation and less than 1%hydrogenation of the aldehyde to make alcohol was observed using thedisclosed catalyst precursor.

Example 3: Representative Active Catalysts

A variety of chelating bisphosphine ligands were examined for theireffect on the hydroformylation activity and selectivity of themonometallic cationic Co(II) catalyst system (BF₄ ⁻ counter-anion, othernon-coordination anions should work well). The initial hypothesis wasthat the extremely strong chelate effect of 1,2-phenylene-linkedbisphosphines was critically important in stabilizing the low-spin,cationic Co(II) oxidation state; however, further studies demonstratedthat other chelating bisphosphine ligands work well. The strength of thebisphosphine chelate, is clearly important for the overall catalyststability, but the effect of the phosphine R-groups is even moredramatic.

The following phosphines have been tested using the cationic cobalt(II)acac catalyst precursor motif. The most successful ligands, which have abridging 1,2-phenylene or saturated alkyl group, generate activecationic Co(II) hydroformylation catalysts. All have similar L:Bselectivities around 1:1 for simple 1-alkenes (e.g., 1-hexene).

The 1,2-phenylene-linked bisphosphines were found to exhibit higherstability at higher temperatures (e.g., 160° C.). Although not wishingto be bound by any particular theory, the strong chelate effect forthese phosphines appears to play an important role in inhibitingcatalyst decomposition reactions. The ethylene- and propylene-basedchelating bisphosphines work well at lower temperatures (140° C.), butshow more tendency to decomposition reactions as the temperatureapproaches 160° C., with extensive catalyst degradation above 160° C.The more electron-rich alkylate phosphines show hydroformylationactivity at lower temperatures (120° C.) relative to thephenyl-substituted ligands that do not start hydroformylating untilaround 140° C.

The bisphosphine ligands that generate less active cationic Co(II)hydroformylation catalysts are shown below. A common feature thatconnects these chelating phosphines is the size of the substituents.Without wishing to be bound by a particular theory, it is possible thatonce a certain R-group steric threshold is passed, hydroformylationactivity becomes more limited.

There are high quality crystal structures of first- and second-row metalcomplexes with many of these ligands, one example is:Ni(F)(CH₃)[d(iPr)pe], d(iPr)pe=(iPr)₂PCH₂CH₂P(iPr)₂, (REFCODE=CAQVIA;Cempora, eta al., Organometallics, 2005, 24, 2827). Stick andspace-filing models from the X-ray structure of Ni(F)(CH₃)[d(iPr)pe] areshown in FIG. 3 to show the blocking of axial coordination sites on thenickel center.

In one aspect, a common feature of all the ligands tested that generateless active cationic cobalt(II) hydroformylation catalysts is that theyblock the axial coordination sites enough so that CO cannot coordinateto the axial sites. Although not wishing to be bound by any particulartheory, CO coordination to both of the axial sites appears to becritically important for the functioning of the cationic catalystdescribed herein.

Table 1 shows the effect of pressure on the hydroformylation of 1-hexeneat 160° C. using the (Et₂P)₂-1,2-C₆H₄ ligand system. The initialturnover frequency (TOF) steadily increases with increasing partial COpressure. The L:B ratio slightly increases at 1000 psig H₂/CO to 1.3:1,consistent with better CO migratory insertion for the linear alkylintermediate and reduced alkene isomerization. Increases in initial TOFhave been observed at pressures up to 1500 psig, though it is possiblethat this effect can be extrapolated to even higher pressures.

This positive CO pressure effect is unprecedented for hydroformylationcatalysts. All good hydroformylation catalysts studied have an inverseCO pressure effect on the rate. Although not wishing to be bound by anyparticular theory, these results suggest that the enhanced efficacy ofthe catalysts described herein is due to the combination of cationiccharge, Co(II) oxidation state, and odd electron count a.

In situ FT-IR studies indicate that the starting [Co(acac)(P₂)]⁺ complexinitially reacts with CO via the equilibrium shown in FIG. 4A. Two CObands appear in the FT-IR spectrum at 1922 and 1940 cm⁻¹. The higherenergy shoulder is assigned to the 19e− dicarbonyl complex, while the1922 cm⁻¹ band is due to the 17 e− complex with just one CO coordinated.H₂ begins to react once the temperature increases above 40° C., favoringfaster CO dissociative processes, to kick off the protonated acac ligandand generating the 17e− hydrido-carbonyl complex [HCo(CO)₂(P₂)]⁺.Subsequent studies carried out under pure CO show that 17e−[HCo(CO)₂(bisphosphine)]⁺ has a carbonyl band around 1940 cm⁻¹, whilethe 19e− [HCo(CO)₃(bisphosphine)]⁺ has a carbonyl band at 2090 cm⁻¹ (seeExample 6 below and FIG. 8).

The ability to add ligands and access 19e− complexes is a key featurefor the exceptional activity of the cationic Co(II) catalysts describedherein. For example, the 18e− [V(CO)₆]⁻ anion is extremely stable due tothe strong π-backbonding to the CO ligands (FIG. 4B), so the associativesubstitution reaction has a high activation barrier to the formation ofthe high energy seven-coordinate 20e− intermediate [V(CO)₆(PPh₃)]⁻(Basolo, et al, J. Am. Chem. Soc., 1984, 106, 71-76). In markedcontrast, the 17e− V(CO)₆ radical is extremely reactive to theassociative substitution and readily proceeds through theseven-coordinate 19e− complex, V(CO)₆(PPh₃). The experimental data fullysupport an associative substitution with a rate law of:rate=k[V(CO)₆][PPh₃], showing second order kinetics. The entropycomponent of the activation barrier, ΔS^(‡)=−28 J/molK, is alsoconsistent with an associative substitution via a 19e− species. Once the19e− complex has formed, the half-occupancy of a metal-ligandantibonding orbital labilizes a carbonyl ligand. The much loweractivation barrier and lower energy for the 19e− intermediate for ligandaddition to a sterically unencumbered 17e− complex makes this a facilereaction.

This lower energy 17e− to 19e− ligand addition process appears to play akey role in the hydroformylation activity of the cationic Co(II)complexes described herein. FIG. 5 shows a mechanism forhydroformylation that proceeds through 5-coordinate 17e− and6-coordinate 19e− complexes. The key step in the reaction is thelabilization of the equatorial CO ligand, trans to the chelatingphosphine, which is normally the stronger coordinated carbonyl ligand.DFT calculations and crystal structures of related chelated bisphosphinecomplexes clearly indicate that the axial coordination sites are notopen enough to coordinate internal alkenes. This is especially true forinternal alkenes with nearby branches, which exhibit highhydroformylation rates using catalysts of the present disclosure.Forming the six-coordinate 19e− complex, [HCo(CO)₃(P₂)]⁺, helps labilizeall the CO ligands, but the most important one is the more stronglycoordinated equatorial Co—CO that needs to dissociate in order tocoordinate the alkene and initiate catalysis.

The cationic charge also appears to be quite important to reduce theelectron density on the cobalt and weaken the π-backbonding to thecarbonyl ligands. The positive charge also increases theelectrophilicity of the cobalt center for branched internal alkenes thatare normally difficult to coordinate to most hydroformylation catalysts.

The ability to add a CO to the 5-coordinate 17e− [HCo(CO)₂(P₂)]⁺ complexforming the 6-coordinate 19e− complex, [HCo(CO)₃(P₂)]⁺, helps todramatically labilize the equatorial CO and allow alkene coordinationinto the least sterically hindered coordination site on the cobalt.Although not wishing to be bound by any particular theory, the 19e−catalyst formation suggests almost all the extremely unusual features ofthis cationic Co(II) catalyst, including the positive effect ofincreasing CO pressure on this catalyst and that more electron-richphosphines show increased activity at lower temperatures and pressures.All even-electron hydroformylation catalysts are slowed or deactivatedby using more electron-rich phosphines. Making the cationic cobaltcenter more electron-rich, however, favors CO coordination to form the19e− complex at lower temperatures and pressures. Once the 19e− complexis formed, equatorial CO lability is dramatically increased.

Chelating phosphine ligands that block the cobalt axial coordinationsites deactivate the catalyst. Although not wishing to be bound by anyparticular theory, this appears to be a steric effect that affects theaxial sites far more than the equatorial sites. Catalyst activityappears to be directly related to the need to form highly labilesix-coordinate 19e− complexes. If the axial sites are blocked, onecannot access the 19e− complexes to labilize the equatorial CO ligandand allow alkene coordination.

For the chelating phosphines that work well, changing the ethyl R-groupsto phenyl, and vice versa, has almost no effect on the aldehyde L:Bregioselectivity. Although not wishing to be bound by any particulartheory, this result suggests the importance of the less stericallyhindered equatorial site for the alkene coordination to initiatecatalysis, and not one of the axial sites. Since the phosphine R-groupstend to point up or down from the equatorial coordination plane, they donot have much steric directing effect on the equatorial alkene-hydridemigratory insertion reaction to make linear or branched alkyls.Therefore, chelating phosphines that will increase the L:Bregioselectivity by having more steric control on the equatorial planemay be useful.

Monodentate phosphines tested so far are not useful ligands forhydroformylation using this cationic Co(II) system. Chelating phosphinesimpose the idea coordination geometry and help stabilize the catalystwith respect to degradation reactions. The cationic charge, higheroxidation state of the cobalt center, and key ability to access highlylabile 19e− complexes compensates for having two donating phosphineligands that would kill a “regular” neutral, even-electron count cobaltcatalyst.

One aspect of this cationic Co(II) catalyst that is not fully understoodis the fact that the weaker chelating phosphines work well at 140° C.and relatively high pressures (still testing the limits). Extensive workon dicationic dirhodium oxo catalysts, [Rh₂(μ-H)₂(CO)₂(et,ph-P4)]²⁺,demonstrate facile phosphine chelate arm dissociation at 90° C. and 90psig (6.2 bar) 1:1 H₂/CO (acetone solvent). This chelate armdissociation leads to fragmentation of the Rh₂ catalyst into inactivemonometallic and double-P4 ligand coordinated dimers.

First row metals usually have weaker metal-ligand bonds, so the apparentstability of [HCo(CO)_(x)(P₂)]⁺ with simple ethylene-bridged chelates athigher temperatures and pressures is notable. Although not wishing to bebound by any particular theory, one explanation is that theelectrophilic cobalt center has a much stronger coordination preferencefor donating ligands like phosphines, especially in the presence ofπ-backbonding carbonyls.

Both Shell and ExxonMobil start with Co(II) salts as precursors forgenerating the HCo(CO)₄ and HCo(CO)₃(PR₃) catalysts, however they maynot see this kind of highly active Co(II) cationic catalyst because ofthe catalyst precursor employed. Shell, for example, often uses aCo(alkoxide)₂ starting material and activates it under H₂/CO in thepresence of phosphine. This chemistry eventually leads to the formationof Co₂(CO)₆(PR₃)₂, which then reacts with H₂ to form the neutral 18e−catalyst: HCo(CO)₃(PR₃).

By starting with a cationic starting material, [Co(acac)(P₂)](BF₄), witha chelating phosphine, good acac leaving group, and an “inert” BF₄counter-anion, the catalysts herein may be useful to stabilize theCo(II) d⁷ oxidation state and maintain the important cationic charge. Asimilar effect is seen with dirhodium tetraphosphine hydroformylationcatalyst systems. A neutral precursor such asRh₂(μ³-allyl)₂(rac-et,ph-P4) results in a terrible neutral dirhodiumhydroformylation catalyst system with rhodium centers in the +1 and 0oxidation states (Chem. Comm., 1998, 2607-2608). On the other hand, thedicationic precursor, [Rh₂(nbd)₂(rac-et,ph-P4)](BF₄)₂(nbd=norbornadiene)results in a highly active and selective hydroformylation system (Angew.Chemie. Int. Ed., 1996, 35, 2253-2256) where the cationic Rh centers arein the unusual +2 oxidation state. Thus, the starting material andligands used can be important.

Example 4: Cobalt Hydroformylation of 1-Alkenes

The data in Example 1 were further elaborated upon by the studies in thepresent example. Briefly, an electron-rich DEPBz bisphosphineligand-based Co(II) catalyst, [Co(acac)(DEPBz)](BF₄), was prepared asdescribed above in Example 1 and utilized in hydroformylation of1-hexene. The catalyst precursors and various ligands and the ligandabbreviations used are shown in FIG. 6. The data below, in Table 2, showfurther data pertaining to temperature and pressure dependency ofhydroformylation of 1-hexene with the disclosed catalyst,[Co(acac)(DEPBz)](BF₄). In the table, DEPBz=(Et₂P)₂-1,2-C₆H₄. Allreactions run for 2 hrs with 1.0 M 1-hexene, 1.0 mM catalyst, 0.1 Mheptane as internal standard, 1:1 H₂/CO in dimethoxytetraglyme (t-glyme)solvent. TOF=initial turnover frequency based on a 5 min sample. Productanalysis determined by GC/MS. Results are based on three or moreconsistent runs with standard deviations given in parentheses. Noalcohol production was observed.

TABLE 2 Temperature and Pressure Dependent Studies for theHydroformylation of 1-hexene with [Co(acac)(DEPBz)](BF₄). Temp PressureInitial TOF Aldehyde Aldehyde Alkane Isomerization (° C.) (bar) (min⁻¹)(%) L:B (%) (%) 120*  50 25.4(5.0) 74.6(5.4) 1.6 0  7.9(1.1) 140  5061.5(6.1) 84.7(1.2) 1.3 0 10.0(1.2) 160**  50 76.8(2.0) 78.2(4.9) 1.11.3(0.3) 19.5(1.0) Pressure Temp Initial TOF Aldehyde Aldehyde AlkaneIsomerization (bar) (° C.) (min⁻¹) (%) L:B (%) (%)  30* 140 40.0(5.1)73.7(1.5) 1.0 0.5(0.4) 21.8(1.7)  50 140 61.5(6.1) 84.7(1.2) 1.3 010.0(1.2)  70 140 36.7(3.5) 79.3(2.2) 1.6 0 10.7(0.9)  90 140 21.7(2.3)82 5(2.6) 1.8 0  8.1(0.6) *The reaction mixture was heated to 160° C.for 5 mins to activate catalyst then cooled to operating temperaturebefore the alkene was injected. **Some black cobalt metal deposition wasobserved inside the autoclave which is suggestive that some catalystdecomposition occurred.

The data in Example 1 are further elaborated upon by the studies in thepresent example. Briefly, an electron-rich DPPBz bisphosphineligand-based Co(II) catalyst, [Co(acac)(DPPBz)](BF₄), was prepared asdescribed above and utilized in hydroformylation of 1-hexene. The tablebelow shows data obtained using the DPPBz bisphosphine ligand-basedCo(II) catalyst. In the table below, DPPBz=(Ph₂P)₂-1,2-C₆H₄. Thecatalyst conditions used were as follows: 1 mM catalyst (61 ppm Co), 1 M1-hexene, 0.1 M heptane standard, solvent=dimethoxytetraglyme (t-glyme),1:1 H₂:CO, 1000 rpm stirring under constant pressure. TOF=initialturnover frequency based on a sample taken at 2 min. Other results basedon sampling after 1 hour. The data below shows that the DPPBzbisphosphine ligand-based Co(II) catalyst shows a catalytic rateincrease dependence on carbon monoxide pressure over a larger pressurerange. It starts slowing around 100+ bar of 1:1 H₂/CO pressure.

TABLE 3 Temperature and Pressure Dependent Studies for theHydroformylation of 1-hexene with [Co(acac)(DPPBz)](BF₄). Temp PressureInitial TOF Aldehyde Aldehyde Alkane Isomerization (° C) (bar) (min⁻¹)(%) L:B (%) (%) 120* 50 26.5 59.4 1.7 0 7.6 140* 50 43.6 71.3 1.3 0.317.9 160 50 66.0 76.8 1.1 1.4 18.9 Pressure Temp Initial TOF AldehydeAldehyde Alkane Isomerization (bar) (° C.) (min⁻¹) (%) L:B (%) (%)  30**160 52.5 49.0 0.94 1.4 45.7  50 160 66.0 76.8 1.1 1.4 18.9  70 160 94.884.0 1.3 1.2 12.1  90 160 103.2 87.3 1.4 1.0 9.1 *The reaction mixturewas heated to 160° C. for 5 mins to activate the cata yst then cooled tooperating temperature before alkene injection. The TOF indicates initialturnover frequency based on a 2 min sample. **Some black cobalt metaldeposition was observed inside the autoclave which is suggestive thatsome catalyst decomposition occurred.

The data in the foregoing data show that a disclosed more electron-richDEPBz-based catalyst shows some slowing above 50 bar of H₂/CO pressure,whereas a disclosed [Co-DPPBz]+ catalyst shows a steady increase in therate of hydroformylation as the H2/CO pressure is increased from 30 to90 bar at 160° C. That is, the [Co-DPPBz]+ catalyst system does not showslowing until about 100 bar of H₂/CO pressure.

Example 5: Cobalt Hydroformylation of Internal Branched Alkenes

The data in Example 2 were further elaborated upon by the studies in thepresent example that compare various disclosed bisphosphine Co(II)cationic catalyst precursors to conventional rhodium-based catalystsprepared as described herein above. The biphenphos ligand is asdescribed herein and FIG. 7. Briefly, reactions were run with 1.0 M3,3-dimethylbutene, 1.0 mM catalyst, 0.1 M heptane as internal standard,and 1:1 H₂/CO. The representative disclosed cobalt precursors used were[Co(acac)(bisphosphine)](BF₄). Results are based on three or moreconsistent runs with standard deviations given in parentheses. Reactiontimes for were as follows: (a) cobalt catalysts were run for 2 hours;and (b) the rhodium catalysts were run for 20 mins. The k(obs) wasdetermined by gas consumption analysis under constant pressureconditions. Cobalt reactions were run in t-glyme solvent and activatedat 160° C. for 5 mins then cooled to operating temperature before thealkene was injected. Rh(acac)(CO)₂ was used as the catalyst precursorand run in toluene with the following excess phosphine:Rh ratios: 3:1for the chelating biphenphos ligand, and 400:1 for PPh₃:Rh. No excessphosphine was used for the cobalt runs. Data obtained forhydroformylation of 3,3-dimethylbutene by the disclosed representativecobalt catalysts and conventional rhodium catalysts are provided inTable 4 below.

TABLE 4 Hydroformylation of 3,3-Dimethylbutene by Cobalt and RhodiumCatalysts. Temp Press Time Aldehyde Aldehyde Alkane k(obs) × 10⁻⁴Catalyst (° C.) (bar) (min) (%) L:B (%) (M sec⁻¹) [Co:DFPBz]⁺ 140 30 12060.0(3.8) 58 0.8(0.02) 1.4(2) [Co:dppe]⁺ 140 30 120 64.1(3.5) 571.0(0.1) 1.5(1) [Co:depe]⁺ 140 30 120 77.1(1.0) 54 1.2(0.05) 2.1(1)[Co:DEPBz]⁺ 140 30 120 84.8(1.7) 51 1.2(0.1) 2.6(1) Rh:biphenphos 120 15 20 96.4(0.2) All linear 3.3(0.06)  25(1) Rh:PPh₃ 120 10.3  20 91.1(2.1)34 0.3(0.04)  21(2)

Further studies were carried out using the HCo(CO)₄ catalyst, thehigh-pressure, unmodified Co(I) catalyst system, the cationicCo(II)-depe catalyst, and two conventional rhodium phosphine catalystsin the hydroformylation reaction using sterically hindered, internalbranched alkenes. The catalysts were prepared as described herein above.Briefly, all reactions were run for 6 hrs with the indicated alkene (1.0M) with 1.0 mM catalyst and 1:1 H₂/CO, using 0.1 M heptane as aninternal standard. Results shown below in Table 5 are based on anaverage of two to four runs. Co₂(CO)₈ or Co(hexanoate)₂ was used togenerate HCo(CO)₄ and all the cobalt reactions were run in t-glymesolvent. [Co(acac)(depe)](BF₄) was used as the cationic Co(II)precursor, depe=Et₂PCH₂CH₂PEt₂. Rh(acac)(CO)₂ was used as the catalystprecursor and run in toluene with the following excess phosphine:Rhratios: 3:1 for the chelating biphenphos ligand, and 400:1 for PPh₃:Rh.No alcohol production was observed. The data are provided in Table 5below.

TABLE 5 Hydroformylation Results for Internal Branched Alkenes usingDifferent Catalysts. Temp Press Aldehyde Aldehyde Alkane Isomer AlkeneCatalyst (° C.) (bar) (%) L:B (%) (%)

HCo(CO)₄ [Co:depe]⁺ Rh:biphenphos Rh:PPh₃ 140 140 120 120 90   30   15  10.3 36.5 24.9 0  0  All linear All linear — — 0   0   0   0    4.8 10.00  0 

HCo(CO)₄ [Co:depe]⁺ Rh:biphenphos Rh:PPh₃ 140 140 120 120 90   30   15  10.3 28.6 26.9  0.8 0  All linear All linear All linear — 2.2 3.7 0  0   14.2 33.5  2.8 0 

HCo(CO)₄ [Co:depe]⁺ Rh:biphenphos* Rh:PPh₃ 140 140 120 120 90   30  15   10.3 77.7 54.7  81.7* 62.0 6.2 4.4 28   0.4 0   0   1.9 0   10.432.1 14.8  8.4 *The Rh:biphenphos catalyst decomposed after about 3hours, with cessation of hydroformylation.

Example 6: Infrared Spectroscopic Study of [Co(Acac)(DPPBz)](BF₄)Catalyst Precursor

A high pressure infrared (IR) spectroscopic study was carried out of the[Co(acac)(DPPBz)](BF₄) catalyst precursor under various pressures ofpure carbon monoxide. The data show that the 17e− [Co(acac)(CO)(DPPBz)]⁺species has a carbonyl stretching frequency at 1937 cm⁻¹, whereas the19e− [Co(acac)(CO)2(DPPBz)]⁺ complex has a higher CO stretchingfrequency at 2090 cm⁻¹. The data are shown in FIG. 8.

Example 7: Catalytic Turnover Studies Usingi[Co(acac)(bisphospine)](BF₄) with 1-Hexene

Briefly, all catalytic runs were done in dimethoxytetraglyme (t-glyme)solvent at 160° C. using 1:1 H₂:CO. Parameters for the 1.2 Million TONrun: 3 μM catalyst (0.000186 g, 0.24 ppm Co) in 6 M 1-hexene (45.45 g,68 mL) with 18 mL of t-glyme and heptane as internal standard. Thereaction was run at 160° C. under 50 bar (725 psig) of syn gas for 14days (336 hrs). The room temperature catalyst was pressure injected intothe hot alkene to initiate the reaction. Using the heptane internalstandard, adjustment for the heavy ends of product distribution is asfollows: 2% 1-hexene, 1.2% alkane, 40.8% iso-hexenes, 33.4% aldehyde(over half 2-methyl hexanal), 1.1% alcohol, 21.5% heavy ends (mostlyaldehyde dimers and trimers). Data are provided in Table 6 below. In thetable, the catalyst is used was [Co(acac){(R₂P)₂-1,2-C₆H₄)}](BF₄), withthe R group as indicated in the table, and other conditions as indicatedtherein. Briefly, the data show that the cationic Co(II) catalystperformed within acceptable parameters through to the time when eachreaction was stopped. The data show that as 1-hexene concentrationdecreases, the catalyst operates more slowly with first order kineticsin 1-hexene over the concentration ranges studied.

TABLE 6 High Turnover Extended Catalysis Runs for 1-HexeneHydroformylation using [Co(acac){(R₂P)₂-1,2-C₆H₄)}](BF₄) at 160° C. TimeAvg TOF Aldehyde Isomer Alkane Catalyst (hr) (min⁻¹) (TON) L:B (%) (%) R= Et (55.2 bar) 3 58.6 10600 19.3 0.3 [Co] = 0.01 mM [Co] = 0.61 ppm[1-hexene] = 1M 20 48.6 58,200 1.2 34.4 1.0 R = Ph (50 bar) 24 64.893,000 24.2 0.4 [Co] = 6 μM [Co] = 0.48 ppm [1-hexene] = 6M 41 74.6179,000 0.9 34.2 0.5 R = Ph (50 bar) 336 59.5 1,200,000 0.9 40.8 1.2[Co] = 3 μM (2 weeks) (includes [Co] = 0.24 ppm 21.5% heavy [1-hexene] =6M ends)

The disclosures of each and every patent, patent application, andpublication cited herein are hereby incorporated herein by reference intheir entirety. While this disclosure has been disclosed with referenceto specific aspects, it is apparent that other aspects and variations ofthis disclosure may be devised by others skilled in the art withoutdeparting from the true spirit and scope of the disclosure. The appendedclaims are intended to be construed to include all such aspects andequivalent variations.

1. A compound of formula I or a salt, solvate, or stereoisomer thereof;

wherein in formula I: X is selected from the group consisting of O, NR³,and CR⁹R¹⁰, wherein R⁸, R⁹, and R¹⁰ can be the same or different and areeach independently selected from the group consisting of H, C₁-C₅ alkyl,C₂-C₅ alkenyl, C₁-C₅ alkoxy, C₁-C₂₀ alcohol, C₃-C₆ cycloalkyl, C₃-C₆cycloalkoxy, C₆-C₁₀ aryl, C₆-C₁₀ alkaryl, C₆-C₁₀ aralkyl, C₄-C₁₀heteroaryl, and combinations thereof; or optionally R⁹ and R¹⁰ cantogether form a C₃-C₆ cycloalkyl ring; each occurrence of Yindependently represents a divalent linking group selected from thegroup consisting of C₁-C₆ alkyl, C₁-C₆ alkenyl, C₆-C₁₄ aryl, C₄-C₁₄heteroaryl, O, NR⁴, and combinations thereof; each occurrence of R¹, R²,R³, and R⁴ is independently selected from the group consisting of C₁-C₂₀alkyl, C₁-C₈ alkoxy, C₁-C₂₀ alcohol, C₃-C₆ cycloalkyl, C₃-C₆cycloalkoxy, C₆-C₁₀ aryl, C₆-C₁₀ alkaryl, C₆-C₁₀ aralkyl, C₄-C₁₀heteroaryl, and combinations thereof; or R² and R³ may optionally bejoined together to form a ring; or optionally one of R¹ and one ofeither R⁹ or R¹⁰ may together form a ring; M¹ and M² each independentlyrepresent a transition metal selected from the group consisting of Fe,Co, Ni, Cu, Ru, Rh, Pd, Ir, and Pt, and M¹ and M² can be the same ordifferent; n is an integer between 0 and 4, wherein the value of thenumber n for the ligand L¹ depends on the transition metal M¹ and isselected such that the transition metal M¹ has 14, 15, 16, 17, 18, or 19valence electrons; m is an integer between 0 and 4, wherein the value ofthe number m for the ligand L² depends on the transition metal M² and isselected such that the transition metal M² has 14, 15, 16, 17, 18, or 19valence electrons; p is an integer between 0 and 4; and L¹ and L² can bethe same or different and each occurrence is independently selected fromthe group consisting of trialkylphosphine, tricycloalkylphosphine,diethyl ether, tetrahydrofuran, H₂O, CO, acetylacetonate, acetate, C₁-C₆alkoxide, acetonitrile, cyclooctadiene, N(R¹¹)₃, N(R¹¹)₂, C₁-C₆ alkyl,C₄-C₁₀ heteroaryl, C₄-C₁₀ heterocycle, H, Cl, Br, I, and F; wherein R¹¹is H, alkyl, cyclcoalkyl, heteroalkyl, or heterocyclic.
 2. The compoundof claim 1, wherein X is CR⁹R¹⁰.
 3. The compound of claim 1, wherein R²and R³ are each C₁-C₆ alkyl.
 4. The compound of claim 1, wherein R² andR³ are each ethyl.
 5. The compound of claim 1, wherein R¹ is phenyl. 6.The compound of claim 1, wherein Y is 1,2-phenylene.
 7. The compound ofclaim 1, wherein M¹ and M² are each independently selected from thegroup consisting of Co and Rh.
 8. The compound of claim 1, wherein p is2.
 9. The compound of claim 1, wherein L¹ and L² are each independentlyselected from the group consisting of acetoacetonate, acetonitrile,pyridine, and cyclooctadiene.
 10. The compound of claim 1, wherein thecompound of formula I is selected from the group consisting of:


11. A compound of formula (II), or a salt or stereoisomer thereof;

wherein in formula (II): each occurrence of R⁵ and R⁶ is independentlyselected from the group consisting of C₁-C₂₀ alkyl, C₁-C₈ alkoxy, C₁-C₂₀alcohol, C₃-C₆ cycloalkyl, C₃-C₆ cycloalkoxy, C₆-C₁₀ aryl, C₆-C₁₀alkaryl, C₆-C₁₀ aralkyl, or combinations thereof; or R⁵ and R⁶ mayoptionally be joined together to form a ring; Z represents a divalentlinking group selected from the group consisting of C₁-C₆ alkyl, C₁-C₆alkenyl, C₆-C₁₄ aryl, C₄-C₁₄ heteroaryl, O, NR⁴, and combinationsthereof; M is a transition metal selected from the group consisting ofFe, Co, Ni, Cu, Ru, Rh, Pd, Ir, and Pt; q is an integer between 0 and 4;o is an integer between 0 and 4, wherein the value of the number o forthe ligand L depends on the transition metal M and is selected such thatthe transition metal M has 14, 15, 16, 17, 18, or 19 valence electrons;and each occurrence of L can be the same or different and is selectedfrom the group consisting of trialkylphosphine, tricycloalkylphosphine,diethyl ether, tetrahydrofuran, H₂O, CO, acetylacetonate, acetate, C₁-C₆alkoxide, acetonitrile, cyclooctadiene, N(R¹¹)₃, N(R¹¹)₂, C₁-C₆ alkyl,C₄-C₁₀ heteroaryl, C₄-C₁₀ heterocycle, H, Cl, Br, I, and F; wherein R¹¹is H, alkyl, cyclcoalkyl, heteroalkyl, or heterocyclic.
 12. The compoundof claim 11, wherein M is Rh or Co.
 13. The compound of claim 11,wherein L is acetylacetonate.
 14. The compound of claim 11, wherein R⁵and R⁶ are each C₁-C₆ alkyl, phenyl, or cycloalkyl; each of which may beoptionally substituted.
 15. The compound of claim 11, wherein Z is1,2-phenylene, 1,2-ethylene, or 1,3-propylene.
 16. The compound of claim11, wherein q is
 1. 17. The compound of claim 11, wherein the compoundof formula (II) is selected from the group consisting of


18. A method of preparing an aldehyde-containing compound, the methodcomprising contacting an alkene-containing compound with the compound ofclaim 1 in the presence of hydrogen (H₂) and carbon monoxide (CO),whereby the alkene is converted to an aldehyde.
 19. The method of claim18, wherein the concentration of the compound is between 10⁻⁶ M and 10⁻²M.
 20. The method of claim 18, wherein H₂ and CO are present in a ratioranging from about 40:60 to about 60:40.